About all

Reason for high hematocrit: High hemoglobin count Causes – Mayo Clinic


High hemoglobin count Causes – Mayo Clinic

A high hemoglobin count occurs most commonly when your body requires an increased oxygen-carrying capacity, usually because:

  1. You smoke
  2. You live at a high altitude and your red blood cell production naturally increases to compensate for the lower oxygen supply there

High hemoglobin count occurs less commonly because:

  1. Your red blood cell production increases to make up for chronically low blood oxygen levels due to poor heart or lung function.
  2. Your bone marrow produces too many red blood cells.
  3. You’ve taken drugs or hormones, most commonly erythropoietin (EPO), that stimulate red blood cell production. You’re not likely to get a high hemoglobin count from EPO given to you for chronic kidney disease. But EPO doping — getting injections to enhance athletic performance — can cause a high hemoglobin count.

If you have a high hemoglobin count without other abnormalities, it’s unlikely to indicate a related serious condition. Conditions that can cause a high hemoglobin count include:

  1. Congenital heart disease in adults
  2. COPD (chronic obstructive pulmonary disease) exacerbation — worsening of symptoms
  3. Dehydration
  4. Emphysema
  5. Heart failure
  6. Kidney cancer
  7. Liver cancer
  8. Polycythemia vera

Causes shown here are commonly associated with this symptom. Work with your doctor or other health care professional for an accurate diagnosis.

  • Definition
  • When to see a doctor

Dec. 02, 2020

Show references

  1. Hemoglobin. Lab Tests Online. https://labtestsonline.org/understanding/analytes/hemoglobin/tab/test/. Accessed Dec. 30, 2018.
  2. Blood basics. American Society of Hematology. http://www.hematology.org/Patients/Basics/. Accessed Dec. 30, 2018.
  3. Blood tests. National Heart, Lung, and Blood Institute. https://www.nhlbi.nih.gov/health-topics/blood-tests. Accessed Dec. 30, 2018.
  4. Understanding blood counts. Leukemia & Lymphoma Society. https://www.lls.org/managing-your-cancer/lab-and-imaging-tests/understanding-blood-counts. Accessed Dec. 30, 2018.
  5. Tefferi A. Clinical manifestations and diagnosis of polycythemia vera. https://www.uptodate.com/contents/search. Accessed Dec. 30, 2018.
  6. Tefferi A. Diagnostic approach to the patient with polycythemia. https://www.uptodate.com/contents/search. Accessed Jan. 3, 2019.


What to Include in the Workup of an Elevated Hemoglobin Concentration and Hematocrit?

What to Include in the Workup of an Elevated Hemoglobin Concentration and Hematocrit?Q:My patient has an elevated hemoglobin concentration and hematocrit; however, the reticulocyte count, ferritin level, results of hemoglobin electrophoresis, and total iron-binding capacity are normal. What is the next step after common causes of an elevated hemoglobin concentration and hematocrit, such as chronic obstructive pulmonary disease, have been ruled out?
A:First, make sure that the hemoglobin level and hematocrit are truly elevated. Reasons for pseudoelevated values. In some textbooks and many laboratories in the United States and the United Kingdom,”normal ranges” are misstated. This is chiefly because most of the participants in “normal value” studies are iron-deficient blood donors or persons with anemia of other causes. There is overwhelming evidence that values up to 18 g/dL (for hemoglobin concentration) or 53% (for hematocrit) should not be considered elevated in white or Asian men who live at altitudes of 1000 m (approximately 3000 ft) above sea level or less.1 Corresponding cutoff values for white and Asian women are 16.5 g/dL and 48%. African Americans, for unknown reasons, have slightly lower normal limits-by about 0.7 g/dL for hemoglobin concentrations and by about 2% for hematocrit. The upper limit of the normal range in children is lower still. Both hemoglobin levels and hematocrit increase in a linear fashion with altitudes of more than 1000 m above sea level; thus, in mile-high Denver or in Santa Fe, NM, 19 g/dL is a normal hemoglobin concentration in a white man. These upper limits are appropriate for healthy, ambulatory, upright, or seated persons. Recumbency of 30 minutes’ duration or more lowers both hemoglobin concentration and hematocrit by about 5%. Chronic illness also lowers these values, as does blood donation. It is not surprising that measurement of hemoglobin concentration and hematocrit in recumbent, hospitalized patients or in blood donors yields spuriously low “normal ranges.” Thus, if the hemoglobin concentration in a healthy, ambulatory, white man is 18 g/dL, no further evaluation is required. However, it is prudent to determine that this is a stable value rather than an increase from a prior value of 16 or 17 g/dL. If an earlier value is not available, measure the hemoglobin concentration again in 4 to 6 months. hemoglobin concentration again in 4 to 6 months. If the blood sample was drawn in the morning, recheck both hemoglobin concentration and hematocrit in a sample obtained in the afternoon, following unrestricted food and fluid intake. Within-day and day-to-day normal variations in hemoglobin concentration and hematocrit are larger than is generally recognized. It is common to see in the same patient a morning hemoglobin concentration that appears slightly elevated and an afternoon concentration that is normal. Having no fluids for 8 hours overnight reduces plasma volume slightly; the lower hemoglobin value in the afternoon is the result of better hydration. Mild dehydration that results from restriction of food and fluid intake for 8 to 12 hours before patients provide blood samples for laboratory tests can also cause spurious elevations of hemoglobin concentration and hematocrit. If values are high in this setting, recheck them following hydration. Common causes of true elevations. If the hemoglobin concentration and hematocrit are truly elevated, consider the common causes first:

  • Tobacco use, which raises carbon monoxide levels in the blood and leads to a true, although usually mild, erythrocytosis, with hemoglobin concentrations as high as 20 g/dL and hematocrits as high as 60% (in men). Measure the carbon monoxide level in patients in whom tobacco use is the likely cause of their elevated values, and counsel them to quit smoking.
  • Obesity, which is a fairly common cause of erythrocytosis.
  • Diuretic use; mild erythrocytosis can result from the slight reduction in plasma fluid volume produced by these medications.

Chronic pulmonary disease, even when accompanied by hypoxia and cyanosis, is not usually associated with erythrocytosis, except in patients who smoke. This paradox has been recognized for nearly a century, although not explained. It may reflect some form of physiologic compensation, such as changes in erythrocyte diphosphoglycerate2,3 or reduction in physical activity because of compromised pulmonary function. Rare causes. Once the common causes of elevated hemoglobin concentration and hematocrit have been ruled out, consider the rare disorders that can produce this finding:

  • High oxygen affinity hemoglobin variants, such as hemoglobin Malm or hemoglobin Kempsey.
  • Polycythemia vera.
  • Renal or hepatic tumors.
  • Cerebellar hemangioma.
  • Venous to arterial shunting, usually accompanied by cyanosis; this finding indicates a need for cardiac catheterization.

When you suspect an obscure cause of elevated hemoglobin concentration and hematocrit, measure arterial blood gases. Normal arterial oxygen content and normal oxygen saturation of hemoglobin (typically 97% to 100%) are characteristic of high oxygen affinity hemoglobin variants, polycythemia vera, and erythropoietin-producing tumors. Low arterial oxygen content and oxygen saturation of hemoglobin are associated with severe pulmonary disease or erythrocytosis caused by a venous to arterial shunt. An elevated carbon monoxide concentration points to tobacco use or other environmental source of carbon monoxide. Cerebellar hemangioma can be excluded if the patient has no neurologic abnormalities, especially no ataxia. A brain scan is not needed. Erythropoietin-secreting tumors of the kidney or liver can be identified by very high levels of serum erythropoietin. In patients with polycythemia vera or high oxygen affinity hemoglobin variants, serum erythropoietin concentration is normal or low (except following phlebotomy or the spontaneous hemorrhage that often complicates polycythemia vera). Polycythemia vera is usually not difficult to diagnose. Obtain a complete blood cell (CBC) count that includes leukocyte and platelet counts (a reticulocyte count is not needed). Typical findings in patients with polycythemia vera are:

  • Hemoglobin concentration greater than 19 g/dL (higher in those who live at altitudes greater than 1000 m above sea level; lower in women and in African Americans).
  • Hematocrit greater than 59% (higher in those who live at altitudes greater than 1000 m above sea level; lower in women and in African Americans).
  • Leukocyte count greater than 12 X 109 /L.
  • Platelet count greater than 500 X 109 /L.
  • Greatly enlarged spleen that is easily palpable below the left costal margin, except in very obese patients. CT or other imaging studies are rarely required to evaluate spleen size; slight splenic enlargement that is evident only in these studies is not a relevant finding.

These features are unique to polycythemia vera. If the above criteria are met, a blood volume (red cell mass) study is not needed. When findings are equivocal, reexamination of the patient in 4 to 6 months usually clarifies the nature of the problem. In patients whose hemoglobin concentration, hematocrit, leukocyte count, and platelet count are borderline, there is no urgency to diagnose polycythemia vera because at this early stage of the disease there is no treatment that is either effective or appropriate. The principle of primum non nocere applies. When high oxygen affinity hemoglobin variants are the suspected cause of erythrocytosis, obtain a careful family history and CBC data from the patients parents, siblings, and children. These disorders exhibit classic Mendelian inheritance. Normal results on arterial blood gas studies (carbon monoxide, oxygen saturation) indicate a need for a study of the oxygen affinity of hemoglobin (P50 study). This test is available in many laboratories. An oxygen affinity curve with a hyperbolic appearance (rather than the normal sigmoidal configuration) and a P50 value less than 20 torr (mm Hg) (instead of the normal 25 to 30 torr) point to a high oxygen affinity hemoglobin variant. Follow up such results with studies to identify an abnormal hemoglobin concentration as the cause of erythrocytosis; these may include electrophoresis, isoelectrofocusing, amino acid sequence analysis, or DNA sequencing. To best determine which of these tests are appropriate for a given patient, consult with the director of a laboratory that specializes in such studies.


REFERENCES:1. Fairbanks VF, Tefferi A. Normal ranges for packed cell volume and hemoglobin concentration in adults: relevance to “apparent polycythemia.” Eur J Haematol. 2000;65:285-296.
2. Fairbanks VF. Myeloproliferative disease: polycythemia vera: the packed cell volume and the curious logic of the red cell mass. Hematology. 2000;4:381-395. 3. Tefferi A. Diagnosing polycythemia vera: a paradigm shift. Mayo Clin Proc. 1999;74:159-162.

Polycythaemia – NHS

Polycythaemia, also known as erythrocytosis, means having a high concentration of red blood cells in your blood.

This makes the blood thicker and less able to travel through blood vessels and organs. Many of the symptoms of polycythaemia are caused by this sluggish flow of blood.

Symptoms of polycythaemia

Not everyone with polycythaemia has symptoms – but many do.

Make an appointment to see your GP if you have persistent symptoms of polycythaemia. These include:

  • headaches
  • blurred vision
  • red skin – particularly in the face, hands and feet 
  • tiredness
  • high blood pressure 
  • dizziness
  • discomfort in the tummy
  • confusion
  • bleeding problems – such as nosebleeds and bruising
  • gout – which can cause joint pain, stiffness and swelling
  • itchy skin – especially after a bath or shower

When to seek immediate medical advice

Polycythaemia can cause blood clots. These put you at risk of life-threatening problems such as:

  • pulmonary embolisms – a blockage in the blood vessel that carries blood from the heart to the lungs
  • deep vein thrombosis (DVT) – a blockage that forms in the blood vessels in your leg before moving elsewhere in your body

Seek medical help immediately if you or someone you’re with shows signs of DVT or a pulmonary embolism. These include:

  • pain, swelling, redness and tenderness in one of your legs
  • a heavy ache in the affected area
  • warm skin in the area of the clot
  • breathlessness
  • chest or upper back pain
  • coughing up blood
  • feeling lightheaded or dizzy
  • fainting

Polycythaemia also increases your risk of heart attack and stroke. Seek emergency medical help if you think that you or someone you’re with is having a heart attack or stroke.

What causes polycythaemia?

Polycythaemia can be divided into several different types, depending on the underlying cause. In some cases, an underlying cause can’t be identified.

Apparent polycythaemia

“Apparent polycythaemia” is where your red cell count is normal, but you have a reduced amount of a fluid called plasma in your blood, making it thicker.

Apparent polycythaemia is often caused by being overweight, smoking, drinking too much alcohol or taking certain medicines – including diuretics (tablets for high blood pressure that make you pee more).

Apparent polycythaemia may improve if the underlying cause is identified and managed. Stopping smoking or reducing your alcohol intake, for example, may help.

Relative polycythaemia

This is similar to apparent polycythaemia. It can happen as a result of dehydration.

Absolute polycythaemia

“Absolute polycythaemia” is where your body produces too many red blood cells. There are 2 main types:

  • primary polycythaemia – there’s a problem in the cells produced by the bone marrow that become red blood cells; the most common type is known as polycythaemia vera (PV)
  • secondary polycythaemia – too many red blood cells are produced as the result of an underlying condition

Polycythaemia vera (PV)

PV is rare. It’s usually caused by a change in the JAK2 gene, which causes the bone marrow cells to produce too many red blood cells.

The affected bone marrow cells can also develop into other cells found in the blood, which means that people with PV may also have abnormally high numbers of both platelets and white bloods cells.

Although caused by a genetic change, PV isn’t usually inherited. Most cases develop later in life. The average age at diagnosis is 60.

Secondary polycythaemia

Secondary polycythaemia is where an underlying condition causes more erythropoietin to be produced. This is a hormone produced by the kidneys that stimulates the bone marrow cells to produce red blood cells.

Health conditions that can cause secondary polycythaemia include:

How polycythaemia is diagnosed

Polycythaemia can be diagnosed by carrying out a blood test to check:

  • the number of red blood cells in your blood (red blood cell count)
  • the amount of space the red blood cells take up in the blood (haematocrit level)

A high concentration of red blood cells suggests you have polycythaemia.

Polycythaemia is sometimes only discovered during a routine blood test for another reason.

Your GP may refer you to a haematologist (a specialist in blood disorders) for more tests, to confirm the diagnosis and to determine the underlying cause.

These may include:

  • a blood test to look for the changed JAK2 gene
  • an ultrasound scan of your tummy to look for problems in your kidneys

Treatments for polycythaemia

Treatment for polycythaemia aims to prevent symptoms and complications (such as blood clots), and treat any underlying causes.

Venesection (removing blood)

Venesection is the simplest and quickest way of reducing the number of red cells in your blood. It may be recommended if you have PV, a history of blood clots, or symptoms suggesting your blood is too thick.

Venesection involves removing about 1 pint (half a litre) of blood at a time, in a similar way to the procedure used for blood donation.

How often this is needed will be different for each person. At first, you may need the treatment every week, but once your polycythaemia is under control you may only need it every 6 to 12 weeks or less.

For more information, read an NHS leaflet on having a venesection (PDF, 336kb). 

Medicine to reduce red blood cells

In cases of PV, medicine may be prescribed to slow down the production of red blood cells.

Many different medicines are available and your specialist will take into account your age and health, response to venesection and red blood cell count when choosing the most appropriate one for you. Examples include:

  • hydroxycarbamide – this medicine is taken as tablets every morning and is generally tolerated well. But you should not take it if you’re pregnant or trying to become pregnant
  • interferon – this medicine is given by injection into the abdomen or thigh 1 to 3 times a week. You can inject it yourself at home once you’ve become familiar with how to do it. Interferon has the advantage that it can be taken in pregnancy, but it may cause unpleasant side effects, such as hair loss and flu-like symptoms

Medicine to prevent blood clots

If you have PV, daily low-dose aspirin tablets may be prescribed to help prevent blood clots and reduce the risk of serious complications.

You may also be offered treatment with low-dose aspirin if you have apparent or secondary polycythaemia and another health problem affecting your blood vessels, such as coronary heart disease or cerebrovascular disease.

Treating and preventing other symptoms

Some people may also need treatment for any other symptoms or complications of polycythaemia they have, or for any underlying cause of the condition.

For example, you may be given medicine to help relieve itching or manage COPD. Read more about:

treatments for itching

treating COPD

Lifestyle changes that help

As well as improving some cases of apparent polycythaemia, making healthy lifestyle changes can also reduce the risk of potentially serious blood clots for people with all types of polycythaemia.

Having polycythaemia means you’re already at high risk of a blood clot, and being overweight or smoking only increases this risk.

You may find the following advice and information helpful:

losing weight 

healthy weight calculator 

preventing cardiovascular disease 

managing high blood pressure 

stopping smoking

Outlook for polycythaemia

The outlook for polycythaemia largely depends on the underlying cause.

Many cases are mild and may not lead to any further complications. However, some cases – particularly cases of PV – can be more serious and require long-term treatment.

If well controlled, polycythaemia should not affect your life expectancy, and you should be able to live a normal life. However, people with PV can have a slightly lower life expectancy than normal due to the increased risk of problems, such as heart attacks and strokes.

PV can also sometimes cause scarring of the bone marrow (myelofibrosis), which can eventually lead to you having too few blood cells. In some rare cases, it can develop into a type of cancer called acute myeloid leukaemia (AML).

Page last reviewed: 30 April 2019
Next review due: 30 April 2022

Polycythemia Vera – American Family Physician

1. Tefferi A.
Polycythemia vera: a comprehensive review and clinical recommendations. Mayo Clin Proc.

2. Berk PD,
Goldberg JD,
Donovan PB,
Fruchtman SM,
Berlin NI,
Wasserman LR.
Therapeutic recommendations in polycythemia vera based on Polycythemia Vera Study Group protocols. Semin Hematol.

3. Lamy T,
Devillers A,
Bernard M,
Moisan A,
Grulois I,
Drenou B,

et al.
Inapparent polycythemia vera: an unrecognized diagnosis. Am J Med.

4. Hoffman R. Hematology: basic principles and practice. 3d ed. New York: Churchill Livingstone, 2000:1130–55.

5. Tefferi A.
Diagnosing polycythemia vera: a paradigm shift. Mayo Clin Proc.

6. Murphy S.
Diagnostic criteria and prognosis in polycythemia vera and essential thrombocythemia. Semin Hematol.
1999;36(1 Suppl 2):9–13.

7. Polycythemia: primary and secondary. In: Kjeldsberg CR. Practical diagnosis of hematologic disorders. 3d ed. Chicago: ASCP Press, 2000:121.

8. Berlin NI.
Polycythemia vera: diagnosis and treatment 2002. Expert Rev Anti-cancer Ther.

9. Pearson TC,
Guthrie DL,
Simpson J,
Chinn S,
Barosi G,
Ferrant A,

et al.
Interpretation of measured red cell mass and plasma volume in adults: Expert Panel on Radionuclides of the International Council for Standardization in Haematology. Br J Haematol.

10. Pearson TC.
Evaluation of diagnostic criteria in polycythemia vera. Semin Hematol.
2001;38(1 Suppl 2):21–4.

11. Grover SA,
Barkun AN,
Sackett DL.
The rational clinical examination. Does this patient have splenomegaly?. JAMA.

12. Weinberg RS,
Worsley A,
Gilbert HS,
Cuttner J,
Berk PD,
Alter BP.
Comparison of erythroid progenitor cell growth in vitro in polycythemia vera and chronic myelogenous leukemia: only polycythemia vera has endogenous colonies. Leuk Res.

13. Michiels JJ,
Juvonen E.
Proposal for revised diagnostic criteria of essential thrombocythemia and polycythemia vera by the thrombocythemia vera study group. Semin Thromb Hemost.

14. Berk PD, Wasserman LR, Fruchtman SM, Goldberg JD. Treatment of polycythemia vera: a summary of clinical trials conducted by the polycythemia vera study group. In: Wasserman LR, Berk PD, Berlin NI, eds. Polycythemia vera and the myeloproliferative disorders. Philadelphia: W.B. Saunders, 1995:166–94.

15. Diehn F,
Tefferi A.
Pruritus in polycythaemia vera: prevalence, laboratory correlates and management. Br J Haemat.

16. Fruchtman SM, Wasserman LR. Therapeutic recommendations for polycythemia vera. In: Wasserman LR, Berk PD, Berlin NI, eds. Polycythemia vera and the myeloproliferative disorders. Philadelphia: W.B. Saunders, 1995:337.

17. Michiels JJ.
Erythromelalgia and vascular complications in polycythemia vera. Semin Thromb Hemost.

18. Gilbert HS.
Current management in polycythemia vera. Semin Hematol.
2001;38(1 Suppl 2):25–8.

19. Barbui T,
Finazzi G.
Treatment of polycythemia vera. Haematologica.

20. Polycythemia vera: the natural history of 1213 patients followed for 20 Years. Gruppo Italiano Studio Policitemia. Ann Intern Med.

21. Streiff MB,
Smith B,
Spivak JL.
The diagnosis and management of polycythemia vera in the era since the Polycythemia Vera Study Group: a survey of American Society of Hematology members’ practice patterns. Blood.

22. Michiels JJ,
Barbui T,
Finazzi G,
Fuchtman SM,
Kutti J,
Rain JD,

et al.
Diagnosis and treatment of polycythemia vera and possible future study designs of the PVSG. Leuk Lymphoma.

23. Lengfelder E,
Berger U,
Hehlmann R.
Interferon alpha in the treatment of polycythemia vera. Ann Hematol.

24. Silver RT.
Interferon alpha-2b: a new treatment for polycythemia vera. Ann Intern Med.

25. Solberg LA Jr.
Therapeutic options for essential thrombocythemia and polycythemia vera. Semin Oncol.
2002;29(3 Suppl 10):10–5.

26. Physician’s desk reference. 58th ed. Montvale, N.J.: Thomson PDR, 2004.

27. Klasco RK, ed. USP DI drug information for the healthcare professional. Greenwood Village, Colo.: Thomson Micromedex, 2004.

Polycythemia Vera – NORD (National Organization for Rare Disorders)

Lichtman MA, Beutler E, Kipps TJ, Seligsohn U, et al. Eds. Williams Hematology. 7th ed. McGraw-Hill Companies. New York, NY; 2006:779-803.

Algazy KM, Bergman GE. Polycythemia Vera. NORD Guide to Rare Disorders. Lippincott Williams & Wilkins. Philadelphia, PA. 2003:411-412.

Berkow R., ed. The Merck Manual-Home Edition.2nd ed. Whitehouse Station, NJ: Merck Research Laboratories; 2003:102-1027.

Tefferi A, Barbui T. Polycythemia vera and essential thrombocythemia: 2017 update on diagnosis, risk-stratification, and management. Am J Hematol. 2017;92:94-108.

Barbui T, Thiele J, Vannucchi AM, Tefferei A. Rationale for revision and proposed changes of the WHO diagnostic criteria for polycythemia vera, essential thrombocythemia and primary myelofibrosis. Blood Cancer J. 2015;5:e337.

Stein BL, Moliterno AR, Tiu RV. Polycythemia vera disease burden: contributing factors, impact on quality of life, and emerging treatment options. Ann Hematol. 2014;93:1965-1976.

Tefferi A. JAK2 mutations in polycythemia vera ? molecular mechanisms and clinical applications. N Engl J Med. 2007;356:444-445.

Scott LM, Tong W, Levine RL, et al. JAK2 Exon 12 mutations in polycythemia vera and essential thrombocythemia. N Engl J Med. 2007;356:459-468.

Finazzi G, Barbui T. How I treat patients with polycythemia vera. Blood. 2007;109:5104-5111.

Campbell PJ, Green AR. The myeloproliferative disorders. N Engl J Med. 2006;355:452-466.

Tefferi A. Classification, diagnosis and management of myeloproliferative disorders in the JAK2V617F era. Hematology Am Soc Hematol Educ Program.2006;240-5.

Campbell PJ, Green AR. Management of polycythemia vera and essential thrombocythemia. Hematology Am Soc Hematol Educ Program.2005;208-201.

Elliot MA, Tefferi A. Thrombosis and haemorrhage in polycythaemia vera and essential thrombocythaemia. Br. J. Haematol.2005;128:275-90.

Chomienne C, Rain JD, Briere JD, et al. Risk of leukemic transformation in PV and ET patients. Pathol Biol (Paris). 2004;52:289-93.

Stuart BJ, Viera AJ. Polycythemia vera. Am Fam Physician.2004;69:2139-44.

Spivak JL, Barosi G, Tognoni G, et al. Chronic myeloproliferative disorders. Hematology (Am Soc Hematol Educ Program). 2003;200-24.

Kwaan HC, Wang J. Hyperviscosity in polycythemia vera and other red cell abnormalities. Semin Thromb Hemost. 2003;29:451-58.

Nagalla S and Besa EC, Polycythemia Vera. Medscape. Updated: Jun 01, 2018. Available at: http://www.emedicine.com/MED/topic1864.htm Accessed October 8, 2018.

Mayo Clinic for Medical Education and Research. Polycythemia Vera. Feb. 08, 2017. Available at: http://www.mayoclinic.com/health/polycythemia-vera/DS00919 Accessed October 8, 2018.

Leukemia & Lymphoma Society. Polycythemia Vera Facts. Revised April, 2015. Available at: https://www.lls.org/sites/default/files/file_assets/FS13_PolycythemiaVera_FactSheet_final5.1.15.pdf Accessed October 8, 2018.

Polycythemia Vera | Johns Hopkins Medicine

What is polycythemia vera?

Polycythemia vera is a rare blood disorder in which there is an increase in all blood cells, particularly red blood cells. The increase in blood cells makes your blood thicker. This can lead to strokes or tissue and organ damage.

What causes polycythemia vera?

Polycythemia vera is caused by a genetic change (mutation) that develops during your lifetime. It is not an inherited genetic disorder. In most cases it is not known why this happens.

What are the symptoms of polycythemia vera?

When you have more blood and it is thicker than normal, problems can occur. Each person’s symptoms may vary. Symptoms may include:

  • Lack of energy (fatigue) or weakness
  • Headache
  • Dizziness
  • Shortness of breath and trouble breathing while lying down
  • Vision problems, such as double vision, blurred vision, and blind spots
  • Inability to concentrate
  • Night sweats
  • Face and becomes red and warm (flushed)
  • Nosebleeds
  • Bleeding gums
  • Too much menstrual bleeding
  • Coughing up blood
  • Bruising
  • Itchy skin (often after a hot bath)
  • Gout
  • Numbness
  • High blood pressure

These symptoms may look like other blood disorders or health problems. Always see your healthcare provider for a diagnosis.

How is polycythemia vera diagnosed?

Your healthcare provider will take your medical history and give you a physical exam. Your provider may also do blood tests. These tests will check the increased number of red blood cells in your body. They will also check if there are other conditions that could cause your higher red blood cell count.

How is polycythemia vera treated?

Your healthcare provider will figure out the best treatment based on:

  • Your age, overall health, and medical history
  • How sick you are
  • How well you handle certain medicines, treatments, or therapies
  • If your condition is expected to get worse
  • What you would like to do

Treatment may include:

  • Phlebotomy. This procedure removes blood from your body. At first this must be done often, such as every week. Once enough blood has been removed to reduce your body’s iron stores (needed to make blood quickly), you will not need this done as often.
  • Certain medicines, including chemotherapy. The medicines help to stop your bone marrow from making too many blood cells. They also keep your blood flow and blood thickness closer to normal.

What are the complications of polycythemia vera?

Polycythemia vera can be fatal if not diagnosed and treated. It can cause blood clots resulting in a heart attack, stroke, or pulmonary embolism. Liver and spleen enlargement are other possible complications.

Living with polycythemia vera

There is no cure for polycythemia vera, but proper treatment can help to reduce or delay any problems. Work with your healthcare provider to create a treatment plan that fits your needs. You should also be physically active in order to increase your heart rate and improve your blood flow.

Other ways to improve your blood flow include:

  • Stretching your legs and ankles
  • Wearing warm gloves and socks during cold weather
  • Avoiding extreme heat
  • Drinking plenty of water

You should also avoid situations in which you could be hurt, and check your feet for any sores.

Key points about polycythemia vera

  • Polycythemia vera is a rare blood disorder in which there is an increase in all blood cells, particularly red blood cells.
  • The increase in blood cells makes the blood thicker.
  • Thick blood can lead to strokes or tissue and organ damage.
  • Symptoms include lack of energy (fatigue) or weakness, headaches, dizziness, shortness of breath, visual disturbances, nose bleeds, bleeding gums, heavy menstrual periods, and bruising.
  • Treatment may include medicines and phlebotomy, a procedure that removes extra blood from your body.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

  • Know the reason for your visit and what you want to happen.
  • Before your visit, write down questions you want answered.
  • Bring someone with you to help you ask questions and remember what your provider tells you.
  • At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.
  • Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.
  • Ask if your condition can be treated in other ways.
  • Know why a test or procedure is recommended and what the results could mean.
  • Know what to expect if you do not take the medicine or have the test or procedure.
  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.
  • Know how you can contact your provider if you have questions.

Hematocrit/packed cell volume | eClinpath

Hematocrit (HCT) and packed cell volume (PCV) are used to measure red blood cell mass. An increase in red blood cell mass is equivalent to erythrocytosis and a decrease indicates an anemia. Because HCT and PCV are affected by changes in water, the HCT and PCV may be high due to water losses in a dehydrated animal (depending on the extent of dehydration). This can normalize a HCT/PCV in an anemic animal or may increase the HCT/PCV above the upper reference limit in a non-anemic animal, resulting in a relative polycythemia.

Method of measurement

PCV tube

Although used synonymously, HCT and PCV actually represent different ways of measuring the proportion of blood composed of red blood cells.

  • Hematocrit: This is actually a calculated value obtained from modern automated hematology analyzers. It is the product of the mean cell volume (MCV) and the red blood cell (RBC) count, both of which are directly measured by the analyzer. Therefore, if there are any inaccuracies in measurement of the MCV or RBC count, the HCT will reflect those inaccuracies. The formula used to calculate the HCT is as follows:
    HCT = (MCV x RBC count)÷10
    Thus, anything that falsely increases or decreases the MCV (e.g. storage of RBC may result in RBC swelling with an increased MCV, thus falsely increasing the HCT) or RBC count (e.g. hemolysis will decrease) will affect the HCT, but not necessarily, the PCV.
  • Packed cell volume (PCV): This is a directly measured value obtained from centrifuging blood in a microhematocrit tube in a microhematocrit centrifuge. The PCV is measured as the height of the red cell column in a microhematocrit tube after centrifugation (see image at right). It is the quickest and most readily available measure of the red blood cell component of blood. Unlike the HCT, this measurement is affected by plasma trapping and how the red blood cells pack within the column. At Cornell University, we centrifuge microhematocrit tubes for 10 minutes in ruminants versus 3 minutes in other species, because it is thought that red blood cells of ruminant do not “pack” as well as other species, however this remains to be tested.  Examination of the “crit tube” can also provide subjective information about the color and clarity of the plasma (icterus, hemolysis, lipemia), and the size of the “buffy coat” (which contains WBC and platelets).  Additionally, one can score and break the tube as desired to remove the plasma for refractometric protein estimation, or to extrude the buffy coat for smear-making. The “buffy coat smear” has the advantage of providing a concentrated preparation of nucleated cells, which can be useful if looking for low-incidence infectious agents (e. g., Anaplasma organisms in leukocytes).

Units of measurement

Both are expressed as % of the blood (SI units are L/L). The conversion formula to SI units is as follows

% ÷ 100 = L/L

Sample considerations

Sample type

Whole blood, body cavity fluids (PCV only)


EDTA is the preferred anticoagulant. Although citrate can be used, the volume of citrate in the tube (10% of the collection volume) will dilute the PCV or HCT accordingly. Heparinized whole blood can also be used.


HCT and PCV are optimally stable for 24 hours at 4°C. After this time, RBC tend to swell which increases the MCV, falsely increasing the HCT and PCV potentially (RBC do not pack as well). Also red blood cells start to hemolyze with storage, resulting in false decreases in both HCT and PCV.


  • Lipemia, icterus: No effect.
  • Hemolysis: Will decrease the HCT and PCV. This is considered an artifactual decrease with in vitro hemolysis. In an animal with true intravascular hemolysis versus in vitro hemolysis, the PCV or HCT is a better indicator of the oxygen carrying capacity of blood than the hemoglobin (which includes free hemoglobin and that within intact red blood cells, with the latter being the oxygen carriers).

Test interpretation

PCV measurement

Increased values (erythrocythemia, erythrocytosis)

  • ArtifactInsufficient centrifugation speed may falsely increase the PCV if the RBC do not pack properly. With false increases in MCV (e.g. storage of blood), the HCT will be falsely increased, but usually the results do not exceed the upper reference limit (however a mildly anemic animal may no longer appear anemic).
  • Physiologic: Some breeds of dogs may have higher RBC counts, hematocrit and hemoglobin concentration, such as Dachshunds (52% versus 48% HCT [Torres et al 2014]), Greyhounds (average 58-61% in 9-13 month old dogs [Shief et al 2007], average 59% in adult dogs [Campora et al 2011]) and Whippets (Uhriková et al 2014).
  • Pathophysiologic (for more, refer to the erythrocytosis page)
    • Relative change to blood water: Dehydration, splenic contraction secondary to epinephrine (e.g. horses).
    • Absolute increase in RBC mass: Stimulated by erythropoietin (secondary erythrocytosis) or erythropoietin-independent (primary erythrocytosis or polycythemia vera). 

Decreased values

  • ArtifactHemolysis of RBC due to sample collection or storage (in vitro hemolysis). In this setting, the measured hemoglobin is the most accurate measure of the animal’s oxygen carrying capacity and a HCT can be estimated by multiplying the hemoglobin x 3 (RBC contain 1/3 hemoglobin in most species). With false decreases in MCV (e.g. excess EDTA), the HCT will be falsely decreased, but usually the results are not below the lower reference limit.
  • Pathophysiologic: 
    • Relative change to blood water: Over-dilution with fluids, splenic relaxation (anesthetic agents, tranquilizers).
    • Absolute decrease in RBC mass: Indicates a true anemia, due to hemorrhage, hemolysis (intravascular, extravascular) or decreased production. Multiple mechanisms may be operative.

90,000 reasons for high hct levels in men and women

Materials are published for information purposes, and are not a prescription for treatment! We recommend that you consult a hematologist at your hospital!

Co-authors: Markovets Natalya Viktorovna, hematologist

Hematocrit is determined by the ratio of erythrocytes to the total blood volume in the human body. If the hematocrit is elevated – what does it mean? There may be two options: either it is the result of some temporary condition, or it is a serious anomaly that needs to be treated.

The hematocrit level is usually determined using an automatic machine that centrifuges the blood and then gives a ready result.

If the hct hematocrit is increased (in medicine hct are the first letters of the Latin word “ hematocrit “), then additional tests must be done to establish the cause of this pathology.

Causes of high hematocrit

Above normal hematocrit may not necessarily be the result of a disease.Perhaps the whole point is in the physiological processes in the body, which were launched as a compensatory mechanism in response to the influence of the external environment.

The most common causes of elevated hematocrit in adults are:

  • Dehydration or dehydration . It occurs when a person, for some reason, consumes less water than his body needs. As a result, the amount of blood in the circulatory system decreases sharply, therefore, the total volume of plasma also decreases.Dehydration is also caused by such pathological processes as vomiting, diarrhea, overheating of all body systems, or excessive work of the sweat glands. If the body has nowhere to take water, then it takes it from the circulatory system. As a result, the level of red blood cells will be changed and a high hematocrit will be found in a person.
  • Chronic hypoxia , which is characterized by a lack of oxygen in human organs and tissues. Most often, this anomaly is common among patients with diabetes mellitus and those who smoke cigarettes for a long time.The fact is that red blood cells contain hemoglobin, which distributes oxygen throughout the body. If there is not enough oxygen, increased production of red blood cells begins, which leads to an increase in hematocrit.
  • Changes in the composition of atmospheric air entail an increased hematocrit: high in the mountains, the level of oxygen decreases, as a result of which the bone marrow begins to produce red blood cells to cope with hypoxia.
  • Erythremia is a disease associated with stem cells that convert into malignant tumors.
  • Tumors and polycystic kidney and adrenal glands.
  • If the patient has been taking medications for a long time, which are recommended to be drunk only as prescribed by the doctor. Increased hematocrit is observed when taking glucocorticoids and hormonal drugs .
  • All types of anemias, as well as diseases that are caused by a lack of vitamin B12 in the body.
  • Stress in which the patient is constantly.
  • Peritonitis, traumatic lesions, bleeding, internal wounds.

Weakness of the body with anemia

It happens that the reasons for the increase from the norms lie in the inflammatory process that goes on in the body. In women, high hematocrit may occur in the second or third trimester of pregnancy. By the way, the number of red blood cells in the blood is also significantly increased in patients with diabetes mellitus.

Ascites – the accumulation of fluid in the abdominal cavity – is one of the causes of increased hematocrit.

Transient causes that affect the level of red blood cells are also distinguished:

  • Frequent vomiting observed with poisoning or caused by any disease.
  • Intestinal obstruction (if filled with fluid).
  • Diarrhea, which can be caused by blood clots.
  • When the sweat glands are working very hard, there is increased sweating, which contributes to dehydration.
  • Burn disease.

Increased sweating is one of the causes of high hematocrit

Symptoms of an increased hematocrit level

At first, a slight dizziness is felt, the cause of which is that red blood cells in large quantities carry oxygen throughout the body, resulting in mild poisoning.If you do not fight the disease, then nausea appears, a person’s breathing is difficult, limbs go numb and a feeling of daze arises.

Increased rate in a child

Hematocrit is increased not only in men and women, but also in children.

Important. Up to a year, a child has a high level of erythrocytes in the analyzes that is 10-12% higher than normal, but you should not worry about this, since after a year it will return to normal.

In children, the causes of abnormalities can be the same factors as in adults: heart pathologies, various injuries, problems with the respiratory system. A high level of hematocrit may indicate kidney problems – these can be both congenital and acquired diseases.

Indicators of the norm with hematocrit

What is the danger?

What is the danger of an increased hematocrit level for human health? The fact is that with such a pathology, the viscosity of the blood increases, it hardly flows through the vessels, which can cause the formation of blood clots, and in the future, blockage of the vessels. Such an anomaly can cause sudden death.First, small vessels overlap and many blood clots form in them. This may be indicated by tingling in the hands or feet, numbness, and tissue necrosis.

And then the turn of large vessels comes, which can cause such diseases:

  • ischemic stroke;
  • heart attack;
  • acute respiratory failure;
  • 90,025 gangrene of the arms or legs. In the future, the affected limb can be amputated.

Important.Elevated hematocrit needs to be treated urgently, so you should consult a doctor. A specialist may prescribe medicines that thin the blood.

Treatment methods

In some cases, bloodletting ( to 500 ml per day ) may be prescribed, as well as replacement of blood with certain solutions that reduce its viscosity.

But if the doctor, as a result of additional tests, revealed a disease that caused an increase in hematocrit, then this disease is treated as the root cause of the pathological condition. Patients are strictly prohibited from smoking, the doctor may prescribe a certain diet that restricts the consumption of red meat or fatty foods – these foods affect the viscosity of the blood. You will also need to drink as much liquid as possible.

We recommend to study similar materials:

  1. 1. Causes and dangers of an increase in the level of basophils in children
  2. 2. The level of basophils in adults has decreased: how to treat basophilia
  3. 3. Reasons for an increase or decrease in neutrophils in the blood test in children?
  4. 4. What does a high level of neutrophils mean and is it dangerous?
  5. 5. What do elevated eosinophils mean in blood tests in adults?
  6. 6. Proper nutrition with an increased level of bilirubin in the blood
  7. 7. What to do with an increased level of bilirubin during pregnancy?

Increased hematocrit in the blood of a child: what does it mean, causes

In the children’s blood test, there are indicators that are quite understandable to parents, for example, the level of hemoglobin or the number of red blood cells.However, there are also indicators in the form, the meaning of which is unknown. And if they are also elevated, it causes feelings. One of these indicators is hematocrit . What does this mean in the analysis of the child’s blood, what should be the normal hematocrit and why does it increase?

Why determine hematocrit

This parameter of the general blood test indicates the percentage of cells in relation to the total volume of blood.To determine it, a centrifuge is used, as a result of which blood cells settle, and plasma remains at the top.

Evaluation of the hematocrit allows you to see how much blood cells occupy, that is, determines the density of the blood. It evaluates all blood cells at once, that is, leukocytes and platelets, as well as red blood cells. But, since red blood cells predominate among all formed elements, it is their content that most affects the hematocrit.

Norm for children

Hematocrit is measured as a percentage and for each age this indicator will be different. The following results are the norm for children:

An excess of the norm is said if the hematocrit of a newborn baby and a baby is more than 62%, and in children older than a year until adolescence, it exceeds 44%.

Reasons for an increase in hematocrit

A high level of hematocrit does not always indicate a disease. This parameter of the clinical blood test can also increase under the influence of various external or internal factors, when the internal balance in the child’s body is disturbed, which causes the activation of compensatory mechanisms.In such cases, changes in hematocrit are temporary and do not affect the general condition of the child.

Pathological causes of high hematocrit include:

  • Dehydration status. This is a fairly common cause of increased blood density caused by loss of plasma, which can be observed with insufficient fluid intake, overheating, vomiting or diarrhea, intense sweating during exercise. As soon as water is lost by the tissues, the body compensates for its deficiency with fluid from the blood (plasma), which leads to an increased number of blood cells in the bloodstream.
  • Chronic hypoxia. When cells and tissues do not receive oxygen for a long period, it stimulates the increased production of red blood cells in order to eliminate the oxygen deficiency. As a result, the number of red blood cells in the bloodstream rises, which causes a high hematocrit. In this case, the volume of blood remains unchanged. This situation is possible with chronic lung diseases, diabetes mellitus, heart defects, passive smoking, stay in the mountains (mountain air contains less O2).
  • Eritremia . Such a tumor disease that affects the bone marrow becomes the reason for the formation of more blood cells in it. They are released in an increased amount into the peripheral blood and will be determined in a higher percentage.
  • Long-term use of certain drugs. The drugs, due to which the hematocrit increases, primarily include hormonal and diuretics.
  • Burns, trauma and bleeding of different localization. The consequence of such influences will be the loss of blood mainly due to plasma, therefore the hematocrit in the general analysis will be higher.
  • Renal diseases, which in a child can be either acquired (tumors, polycystic and others), and congenital. Due to the increased loss of fluid in the urine, such pathologies provoke blood thickening and an increase in hematocrit.

Why high hematocrit is dangerous

Since an increase in this indicator indicates a more viscous and thicker blood, this threatens the child with the appearance of blood clots, since the blood will move much slower through the vessels, and its cells will stick together.

Blocking small vessels by clots leads to a deterioration in the blood supply to important organs, including the brain and heart. In the worst cases, stroke, gangrene of the extremities, respiratory failure, or heart attack are possible.

What to do

Having identified an increased hematocrit in a child, you should go to a pediatrician for consultation, because such a change in the blood test may not be dangerous, and be a sign of a serious illness. The doctor will be able to correctly decipher the analysis, determine the cause of the increase in blood density and prescribe a treatment that will help return the hematocrit to normal. Blood thinners and other drugs may be used in therapy. Parents will be advised to give their child more to drink, limit foods rich in animal fats or iron in the child’s menu.

90,000 Hematocrit increased, what does this mean?

Hematocrit – part of the total blood volume, which falls on erythrocytes.An increased hematocrit in the blood may be evidence of pathological processes occurring in the body. Sometimes such processes are temporary, in other clinical situations they are the result of serious systemic diseases.

Diagnosis of hematocrit is carried out in a clinic by means of a special device in which the blood is centrifuged. The diagnosis of this indicator, which is designated in medical language as “Hct” (from Latin hematocrit), is carried out as part of a general blood test.To determine the volume of red blood cells, blood is taken from a vein.

Causes of high hematocrit

Physiological causes of increased hematocrit in the blood are not always directly related to certain diseases. Sometimes the body simply tries to maintain internal homeostasis – the balance of physiological processes, achieved by triggering regulatory compensatory mechanisms. In some cases, an increase in hematocrit is a quantitative characteristic of the physiological setting of the body under changed external or internal conditions.

The most common pathological causes of increased hematocrit are:

  • Dehydration.
  • The state of dehydration leads to a decrease in the total volume of blood circulating through the body. This is accomplished by decreasing the amount of plasma. Dehydration can be the result of an elementary lack of water (for some reason, a person consumes less fluid than is necessary for the full functioning of the body). Sometimes dehydration is the result of excessive water loss due to overheating, diarrhea, bouts of vomiting, and intense sweating.Lack of water in cells and tissues is compensated by the body by taking fluid from the bloodstream. At the same time, the ratio of erythrocytes and the liquid component of blood changes, the hematocrit increases.

  • Chronic hypoxia (lack of oxygen in tissues and cells).
  • This pathology is often observed in smokers or in people with diabetes mellitus. Erythrocytes contain hemoglobin, which transports oxygen to cells and removes CO2. In chronic hypoxia caused by objective reasons, the body tries to compensate for the oxygen deficiency and increases the synthesis of red blood cells.In this clinical situation, a high hematocrit is associated precisely with an increase in the number of red blood cells: the total blood volume does not change.

  • Changes in the composition of atmospheric air.
  • A stay in the mountains for several days leads to an increase in the number of red blood cells in the blood. At altitude, the air contains less oxygen, which leads to the occurrence of hypoxia and the start of a compensatory process – an increase in the production of erythrocytes by the bone marrow and other hematopoietic organs of a person.Primary erythremia (polycythemia) is a malignant disease of the hematopoietic organs associated with the transformation of stem cells.

  • Tumors of the kidneys and adrenal glands, polycystic or hydronephrosis of the kidneys.
  • Prolonged uncontrolled intake of medications.
  • Glucocorticoids and other hormonal drugs are especially dangerous in this regard. Diuretics also have a similar effect.

  • Traumatic injuries, burns, internal wounds and bleeding, peritonitis.
  • Anemic conditions associated with iron or vitamin B12 deficiency.
  • Chronic stress.

Sometimes hematocrit is a side symptom of acute or chronic inflammatory processes in the body. Not always, but quite often, an increased number of red blood cells is observed in patients with diabetes mellitus or in pregnant women in 2-3 trimesters with late toxicosis.

The cause of hematocrit can also be ascites – an excessive and abnormal accumulation of fluid in the abdominal cavity.

Often, with an increase in hematocrit, hemoglobin also rises. Find out the symptoms and treatment of high hemoglobin in men, women and children.

Increased hematocrit in a child

In childhood, an increase in the number of red blood cells by 10-12% of the norm may be the result of normal physiological processes. When a child reaches the age of 1 year, the hematocrit stabilizes by itself to the normal level. Such processes should not cause concern for parents or pediatricians; you need to start worrying if an abnormal number of red blood cells persists after a year.

The reasons for a significant excess of the number of erythrocytes in the blood plasma in children can be the same factors as in adults: traumatic injuries, respiratory diseases, cardiac pathologies. Sometimes the situation when the child’s hematocrit is increased is evidence of various renal ailments of a congenital and acquired nature.

Increased hematocrit: what does it mean specifically for the well-being and health of a person? A high Ht index is expressed in an increase in blood viscosity: such blood flows more slowly through the vessels, becomes viscous, which leads to an increase in the risk of thrombosis.

Blockage of the lumen of blood vessels is a serious threat to human health. Blood clots sometimes cause sudden death. First, small blood clots block the smallest capillaries, which causes peripheral disturbances (numbness, tingling in the extremities, tissue necrosis), then the turn of large vessels comes.

Large artery thrombosis can cause:

  • Heart attack.
  • Ischemic stroke.
  • Gangrene of the limb and subsequent amputation.
  • Acute respiratory failure.

In view of the risk of these complications, the thickened blood should be “thinned” to the level of the hematocrit norm. The therapeutic effect is prescribed by the doctor depending on the current clinical situation.

Bloodletting (up to 500 ml per day) and replacement of blood with special solutions that reduce its viscosity are sometimes prescribed as a therapeutic measure.

In other cases, the primary disease is treated.Sometimes patients are strictly prohibited from smoking, along the way, diet therapy is prescribed with a restriction on the amount of red meat and any other foods with a high content of animal fats. Increased fluid intake is also prescribed.

Hematocrit – Blood test – Decoding of analyzes online

Synonyms : hematocrit, HCT, Ht, Crit, packed cell volume, PCV

What is hematocrit?

Hematocrit is the part (%) of the total blood volume, which is made up of erythrocytes, that is, this is the ratio of erythrocytes to blood plasma.

Decipher “Biochemical blood test”
Decipher “General urine test”

Red blood cells carry oxygen throughout the body. Having too many or too few red blood cells in your blood can be a sign of certain medical conditions.

The hematocrit value is often used to assess the severity of anemia, due to which it can drop to 15-25%. Hematocrit should not be assessed immediately after transfusion or blood loss, as this may cause a falsely high or falsely low result.


Hematocrit (Ht) is expressed as a percentage (%) of the total blood volume or in liters per liter (l / l) – the corresponding proportion of formed elements in 1 liter of blood (480 ml of cells in 1 liter of blood = 0. 48 liter / liter = 48%).

Under normal conditions, there is a linear relationship between hematocrit and hemoglobin concentration.

Norm of hematocrit

Normal hematocrit values ​​may differ slightly depending on age, gender, pregnancy, place of residence, and the use of different diagnostic methods.

The following hematocrit values ​​are generally considered normal:

  • Adult Male: 42-54% 90,028
  • Adult women: 38-46% (due to physiological menstrual blood loss, the hematocrit rate in women is lower than in men)

For residents of highlands, hematocrit norms increase with increasing altitude at which people live. This is a consequence of the lower concentration of oxygen in the atmosphere, which is why more red blood cells are needed to provide the body with the necessary amount of oxygen.

Hematocrit can be decreased or increased due to various reasons. But it should be remembered that its level in some cases can be estimated incorrectly (with blood loss, with transfusion, in the mountains). According to research, moving from supine to sitting position can cause clinically significant increases in hemoglobin, hematocrit, and red blood cell count.

Norm of hematocrit during pregnancy

Blood volume increases during pregnancy.But the volume of plasma increases more than the volume of red blood cells, which leads to relative anemia. There is a physiological decrease in the number of red blood cells (RBC), as well as the level of hemoglobin (Hb) and hematocrit (Hct). Different laboratories may have different hematocrit reference values. Below is the approximate blood hematocrit during pregnancy.

In the first trimester of pregnancy, the normal hematocrit is 31-41%. By 6-12 weeks, blood plasma volume has already increased by approximately 10-15%.The blood liquefies, and the concentration of cells in it decreases. Therefore, in a pregnant woman, a slight decrease in hematocrit and hemoglobin is allowed by the end of the first / middle of the second month of pregnancy. If the indicator falls below normal, then we can talk about the manifestation of anemia.

In the second trimester, the volume of circulating blood is steadily increasing. The risk of developing iron deficiency anemia increases during this period. Therefore, obstetricians-gynecologists attach particular importance to the mandatory regular observation of the expectant mother and hematocrit indicators.The reference hematocrit values ​​in the second trimester are 30-39%.

The hematocrit reaches its lowest level in the third trimester. From 30 to 34 weeks of gestation, the fastest rate of increase in the volume of circulating blood is observed, after which this volume changes insignificantly before delivery. The peak of the decrease in hematocrit reaches 33 weeks. A hematocrit below normal (28-40%) should be considered abnormal.

Hematocrit values ​​above normal during pregnancy are also referred to as pathological.

Norm of hematocrit in children

In newborns and especially premature babies, high hematocrit values ​​are normal. If the hematocrit level in the analysis of blood from a vein exceeds 65%, then polycythemia (an increased level of red blood cells) is diagnosed. Closer to three months of age, the hematocrit drops. The reference hematocrit values ​​are approximately 30-44%, depending on the age of the child.

Decreased or increased hematocrit in a child with minor deviations from the norm, most often, is caused by the influence of external factors.If these deviations are significant, then it is necessary to look for the reasons for this condition.

Hematocrit above normal

A high hematocrit may reflect an absolute increase in the number of red blood cells or a decrease in plasma volume. An increase in hematocrit means that the blood thickens, which means that the risk of blood clots increases. This causes oxygen deficiency of the organ in which the thrombus has formed, and, accordingly, a violation of its functions (stroke, heart attack).

Reasons for an increase in the level of hematocrit:

  • Dehydration (with burns, diarrhea, taking diuretics). With sufficient fluid intake, the hematocrit returns to normal.
  • Diseases of the heart and lungs. The body tries to compensate for the lack of oxygen in the blood by producing more red blood cells.
  • Smoking, living high above sea level (compensation for a decrease in oxygen levels in the body)
  • Neoplasms in the kidneys, accompanied by increased production of erythropoietin.
  • Polycythemia vera (polycythemia vera) is a rare disease that causes abnormal production of red blood cells.

High hematocrit during pregnancy

An increased hematocrit in pregnant women signals a thickening of the blood, increasing the load on the cardiovascular system and increasing the likelihood of blood clots.

High hematocrit may be a sign of preeclampsia (gestosis).

High hematocrit in a child

If, when determining the results of a blood test, the hematocrit is very high (more than 65%) in a newborn child, it means that the baby was in a state of hypoxia. That is, the baby experienced oxygen deficiency during the prenatal period or during childbirth. The future development of the baby depends on the duration of the hypoxia period, because during oxygen starvation, the blood supply to the brain is disrupted.

At an older age, the causes of an increase can be the same pathological conditions as in adults.

Hematocrit below normal

A low hematocrit reflects a low circulating red blood cell count and is an indication of a reduced ability to carry oxygen.In this condition, patients have shortness of breath, a constant feeling of fatigue, heart palpitations, pale skin color, hair loss. With a decrease in hematocrit, anemia is diagnosed.

Causes of low hematocrit:

  • Significant blood loss (due to trauma, chronic bleeding).
  • Deficiency of nutrients in the body (iron, folic acid, vitamins B12, B6).
  • Increased destruction of red blood cells (hemolytic anemia, sickle cell anemia).
  • Disorders in the work of the bone marrow (aplastic anemia, cancer, chemotherapy).
  • Kidney disease resulting in decreased production of erythropoietin, a hormone that stimulates the production of red blood cells in the bone marrow.

Low hematocrit during pregnancy

A slight decrease in hematocrit due to increased blood volume is normal during pregnancy. With a decrease in hematocrit below the reference values, one speaks of anemia.

Iron deficiency anemia is the cause of decreased hematocrit during pregnancy in 90% of cases. The state of health of a pregnant woman with a low hematocrit worsens, since the cells of all organs experience oxygen starvation (hypoxia), the alkaline balance is disturbed. Fatigue, weakness, headache, heart palpitations, and shortness of breath may occur. The heart and blood vessels work under increased load, the work of other organs and systems is disrupted.

Low hematocrit in a child

A decrease in hematocrit in children may be due to improper diet (lack of nutrients), and is also observed with a significant growth spurt. These changes can be easily corrected.

Acquired types of anemia, especially iron deficiency anemia, are more common in children over 1 year of age and adolescents. In term infants under 6 months of age, iron deficiency is an unlikely cause of anemia.

Specialized scientific and practical publications for veterinarians and students of veterinary universities.


Journal issues by year

Journal contacts


Subscribe to news

You can subscribe to our newsletter.
To do this, you need to fill out the form, indicating your postal e-mail.
Distribution is carried out no more than 5-6 times a year.
The site administration never, under any circumstances, discloses or transfers to other persons data about site users.

Purchase the paper version

To purchase a paper version of the magazine, you must place an order and pay for it online.
Delivery is carried out by Russian Post.
The cost of a copy of the magazine is indicated including delivery.
For questions about mailing to other countries, please contact the Deputy Editor-in-Chief: [email protected]


Delivery for clinics

For veterinary clinics in St. Petersburg and Len. area.
Delivery is made by courier to the address of the clinic in the amount of one copy.
To arrange delivery, you must fill out the form.The delivery is subscribed to once and is valid until a representative of your organization submits a request to cancel the delivery.

Arrange delivery

90,000 Blood in the stool: causes, symptoms, diagnosis, treatment

For a number of features, the doctor is able to identify a possible source of bleeding and determine its causes. In terms of diagnostics, the rule is relevant: the brighter the blood in the feces, the lower the bleeding area is.This phenomenon is explained by the presence of hemoglobin, which, passing considerable distances along the gastrointestinal tract, becomes oxidized, changing the color of the blood to brown or black.

At first, it is important for a specialist to clarify the source of bleeding and assess the severity of blood loss, since further tactics will depend on this moment. The simplest method is a complete blood count. The main indicators are hemoglobin, hematocrit and erythrocytes. In the future, the doctor prescribes more specific diagnostic methods.

Therapy is based on eliminating bleeding and eliminating its consequences. In simple cases, doctors manage to cope with conservative methods, but sometimes they have to resort to surgical treatment.


Bleeding from the gastrointestinal tract can not always be determined visually, but it is possible to learn about regular blood loss by a number of signs:

  • deterioration of the general condition;
  • 90 025 fatigue;

  • pallor of the skin;
  • dizziness, tinnitus, fainting;
  • high heart rate;
  • heart pain;
  • low pressure;
  • 90 025 brittle nails;

  • hair loss.

The described symptoms are often overlooked, as patients associate them with the usual overwork. Acute bleeding from the gastrointestinal tract manifests itself in a stormy clinic, which develops much faster, while new symptoms appear:

  • vomiting of blood;
  • weakness, trembling, fainting;
  • decrease in the volume of urine, or its complete absence.

Symptoms of the main disease that led to blood loss may come to the fore.Pain syndrome may indicate ischemic processes, intussusception of intestinal loops. At the time of defecation, pain is characteristic of anal fissure or hemorrhoids, while an important sign is the presence of bright blood in the stool.


A bleeding vessel can be localized in any part of the gastrointestinal tract and the exact localization can be detected using special diagnostic methods. Nevertheless, it is possible to identify the main diseases in the clinic of which blood loss is possible:

  • gastric and duodenal ulcer;
  • infectious bowel diseases;
  • diverticula of the esophagus and intestines;
  • mesenteric thrombosis;
  • Crohn’s disease;
  • ulcerative colitis;
  • tumors in decay stage;
  • 90,025 polyps;

  • hemangiomas;
  • hemorrhoids;
  • anal fissure.

In some cases, the cause of blood in the feces can be other diseases of a systemic nature: hemorrhagic vasculitis, hemostasis disorder.


The very first thing that the doctor specifies is the type of blood in the stool. This moment can prompt a specialist to make assumptions about the source and causes of blood loss. The detected signs may be specific for a number of diseases:

  • bright scarlet blood that comes out from the anus in the form of drops or trickles – a characteristic sign of hemorrhoidal bleeding;
  • blood in the feces in the form of scarlet veins – a symptom of a lesion of the sigmoid colon;
  • dark brown blood, evenly mixed with feces, is characteristic of pathological processes localized in the initial section of the large intestine;
  • Black loose stools are a sign of massive bleeding from the esophagus, stomach, or small intestine.

After clarifying the anamnesis, the doctor proceeds to a visual examination and identifying areas of pain. With the help of palpation, you can find painful areas and, accordingly, the localization of the source of bleeding.

The first method of laboratory diagnostics is a blood test, which can be used to track the severity of bleeding and suggest its probable duration.

Instrumental methods are required to help visualize the pathological focus and eliminate it.Based on the available data, the doctor prescribes diagnostic methods that will be informative in each case:

  • contrast-enhanced abdominal X-ray – effective for the diagnosis of ulcers, polyps, tumors, diverticula and intussusception;
  • sigmoidoscopy – a method that helps to detect pathologies of the rectum;
  • colonoscopy is an endoscopic diagnostic method used to visualize the colon.

The peculiarity of endoscopic approaches is the ability to examine the bleeding focus, take histological material and try to stop the bleeding with conservative approaches.


In the treatment of bleeding, doctors strive to fulfill 2 goals:

  • stop bleeding;
  • to correct the developed anemia.

It is most often possible to perform hemostasis with drugs that increase coagulation, gastric lavage with cold water, coagulation through an endoscope. In some cases, the bleeding area cannot be treated with non-invasive methods, then doctors begin surgical treatment.

In the postoperative period, it is very important to eliminate the main causes of the development of pathology and prevent relapses. In case of an ulcer, it is necessary to eradicate H. pylori, suppress the secretion of gastric juice. Early hemorrhoids and anal fissure can also be treated conservatively. But some diseases – polyps, intussusception or diverticula – are eliminated only by surgery.

Chronic bleeding is always accompanied by anemia, therefore it is necessary to correct the loss of hemoglobin, which is achieved by using iron preparations.When shock develops, transfusion of plasma or blood components is considered an indispensable approach.

90,000 High blood pressure or arterial hypertension

If you have high blood pressure (BP).
Examination for arterial hypertension.
Analyzes and studies to identify hypertension (high blood pressure) and complications of high blood pressure.
High blood pressure symptoms.
High blood pressure: what to do.

The article was prepared by a general practitioner of the Center for Immunology and Reproduction Boyko Tatyana Valentinovna

Arterial hypertension (AH) is a set of conditions that are accompanied by a prolonged increase in pressure in the arteries of the systemic circulation.

High blood pressure is very common and significantly affects the quality of life.

Blood pressure is determined by how much blood is emitted by the heart, and how the walls of the arteries respond to this.
You may live for many years with high blood pressure and not be aware of it. At the same time, the lack of control over blood pressure increases the risk of complications, including angina pectoris, stroke, heart attack.

Arterial hypertension develops over many years and eventually affects almost all people. Fortunately, an increase in blood pressure is easy to determine, and therefore, to control and reduce the risk of complications.

There are two types of arterial hypertension, depending on the cause of development:

Primary, or essential, arterial hypertension – a disease caused by an increase in blood pressure, the cause of which is not clear.This disease accounts for about 90% of cases of hypertension.

Secondary or symptomatic is AH with an established cause (renal, endocrine, neurogenic, cardiovascular (hemodynamic), medicinal (iatrogenic), toxic, of various origins (with hypercalcemia, porphyria, late toxicosis of pregnant women and other. Unlike primary hypertension, secondary hypertension develops rapidly and with higher blood pressure.

Many people do not feel any sensation when their blood pressure rises, even if the blood pressure numbers are dangerously high.Some people with high blood pressure experience prolonged pressing headache, dizziness, nosebleeds are possible.

One of the main consequences of a prolonged increase in pressure in the arteries is damage to internal organs (target organs).

Target organs:

Heart. Manifestations: angina pectoris (one of the forms of ischemic heart disease, manifested by chest pain during exercise), myocardial infarction, heart failure, sudden cardiac death.

Brain. Manifestations: thrombosis, hemorrhages, hypertensive encephalopathy (damage to cerebral vessels with prolonged increase in blood pressure), cerebral lacunae (minor hemorrhages in the brain).

Kidneys. Manifestations: microalbuminuria, proteinuria (appearance of protein in the urine), chronic renal failure (significant renal dysfunction).

Vessels. Vessels of the retina (retinopathy – damage to the vessels of the retina), carotid arteries, aortic aneurysm (saccular enlargement of the aorta).

Metabolic syndrome is a group of conditions accompanied by metabolic disorders, accompanied by obesity, increased triglyceride levels, low high-density lipoprotein levels, high blood pressure, high insulin levels, and insulin resistance.

The more components of the metabolic syndrome are present, the greater the likelihood of developing complications – the development of diabetes, heart and brain damage.

  • Family polygenic predisposition – genetic factors (about 30%) associated with the functioning of the renin-angiotensin system
    • congenital disorders of lipid metabolism in the patient himself and his parents
    • diabetes mellitus in the patient and his parents
    • kidney disease
  • Factors related to physical condition, health and living conditions
  • 90,024 90,025 gender and age (in men aged 20-29 – 9.4% of cases, in 40-49 years – 35% of cases, 60-69 years – up to 50%).In women, hypertension develops in 60% of cases during menopause).

  • Obesity (the risk of developing hypertension increases 5 times. More than 85% of patients with hypertension have a body mass index> 25) Calculate body mass index
  • Alcohol abuse
  • Excessive consumption of table salt, which retains fluid in the body, causing an increase in blood volume, which the heart must distill.
  • Insufficient intake of potassium in the diet. Potassium is involved in maintaining the balance of sodium in cells. If potassium is deficient, too much sodium can be stored in the cells.
  • Lack of vitamin D in the diet, which disrupts the regulation of blood pressure in the kidneys.
  • Physical inactivity is an inactive lifestyle leading to obesity and worsening the course of arterial hypertension.
  • Smoking not only raises blood pressure, the chemicals in cigarettes also damage the walls of blood vessels
  • Stress, mental strain
  • Certain chronic diseases such as disorders of fat metabolism, atherosclerosis, diabetes mellitus, kidney disease.

Establishing the etiology (cause) of essential hypertension makes it possible to assess the risk of developing pathological conditions, to prescribe preventive and therapeutic measures in a timely manner. This makes it possible to significantly limit the negative impact of the disease on the patient’s quality of life.

At the same time, the identification of genetic polymorphisms in the genes of key factors in the regulation of the cardiovascular system, primarily those associated with the functioning of the renin-angiotensin system, is acquiring the greatest relevance.The renin-angiotensin system (RAS) or the renin-angiotensin-aldosterone system (RAAS) is a system of enzymes and hormones that regulate blood pressure, electrolyte and water balance.

The renin-angiotensin-aldesterone cascade begins with the glycosylation of prorenin, which turns into an active form – renin (a peptidase enzyme secreted by the kidneys into the bloodstream in response to a stressful situation). Renin cleaves the N-terminal segment from angiotensinogen to form biologically inert angiotensin I .Inactive angiotensin I is hydrolyzed by angiotensin-converting enzyme (ACE), which cleaves the C-terminal dipeptide and, thus, biologically active – angiotensin II is formed. At the moment, the most prognostically unfavorable polymorphic alleles of the RAAS genes, as well as other factors responsible for intracellular ion transport, regulation of aldosterone synthesis and smooth muscle tone, have been established.

In our clinic, you can undergo an examination for polymorphism of genes of vascular tone, which is necessary not only to establish the cause of arterial hypertension, but also to properly treat this disease.In addition to arterial hypertension, there are other reasons that warrant genetic testing. Simultaneously with this profile, the risk of thrombophilic complications is assessed – the most important component of the development of heart attacks, strokes, thromboembolism. The profile is called polymorphism of genes of the hemostatic system. Genetic tests are taken once in a lifetime and allow you to assess the risk of developing a particular pathology. In this case (polymorphism of genes of the hemostasis system and polymorphism of genes of vascular tone), vascular disorders and thrombosis.You can read more about each of them on the pages of these analyzes.

Indications for genetic analysis

  • Ischemic heart disease (IHD)
  • Acute myocardial infarction
  • Stroke
  • Diabetic nephropathy
  • Venous thromboembolism
  • Smoking
  • Placental dysfunction
  • Disorders of microcirculation and vascular tone
  • Diabetes mellitus
  • Selection of drugs for hypertension

More research is needed to correctly diagnose and develop treatment strategies.

First steps and self-examination

  1. Work with your doctor to evaluate risk factors for high blood pressure and complications.
  2. Evaluate your lifestyle in order to reduce risk factors: reducing salt, alcohol consumption, smoking cessation, increasing physical activity, reducing stress reactions, exercising calm and deep breathing.
  3. Measure blood pressure regularly (how to measure blood pressure correctly)
  4. Regularly measure body weight and volume (waist circumference, fat folds)
  5. Get a regular check-up

Genetic tests – given once in a lifetime, at any age

  1. Polymorphism of genes of the hemostasis system
  2. Polymorphism of genes of vascular tone

Basic analyzes for women and men with high blood pressure

  1. General blood test with determination of hematocrit level
  2. General urinalysis
  3. Biochemical blood test
    1. Assessment of carbohydrate metabolism, sugar level: glucose
    2. Evaluation of electrolyte metabolism: potassium, sodium, calcium, phosphates
    3. Renal function assessment: urea, creatinine, uric acid
    4. Evaluation of fat metabolism: cholesterol, HDL, LDL, triglycerides
    5. Assessment of liver and heart damage: AST, ALT
  4. Assessment of vascular wall damage: homocysteine, ultrasensitive C-reactive protein
  5. Extended hemostasiogram to assess blood coagulation and risk of thrombosis
  6. Examination of the thyroid gland: TSH, T4 St., T3 St.
  7. Electrocardiogram
  8. Chest X-ray.
  9. Consultation with a general practitioner / cardiologist with a full range of examinations to receive recommendations for lifestyle changes and treatment.

In the presence of sugar metabolism disorders or a high risk of disorders (high glucose levels, symptoms of diabetes mellitus, diabetes mellitus in relatives)

If you are overweight and have high blood pressure, additional studies are recommended

Hormonal examination for women

Additional tests that a doctor may prescribe for hypertension:

Renin and angiotensin I blood test

Blood test for aldosterone

How to measure blood pressure correctly, why measure pressure on both hands

Blood pressure should be measured 1-2 hours after a meal.For an hour before the measurement, refrain from smoking, eating, coffee, strong tea. Blood pressure should be measured in a sitting position, after a 5-minute rest, without straining the muscles of the arms and legs, without holding your breath during the procedure and without talking to others; the hand on which blood pressure is measured should be at the level of the heart. Measurement of blood pressure should be carried out on both hands and focus on the higher measurement.

What blood pressure numbers are normal and what can be considered high pressure

The numbers of normal blood pressure (BP) range from 90/60 to 139/89 mm Hg, less than 90/60 is arterial hypotension , i.e.that is, a decrease in blood pressure, and above 139/89 – this is arterial hypertension – an increase in blood pressure.

The first number means systolic blood pressure, which depends on the strength and speed of the heart, it is also called “upper”. The second number – diastolic blood pressure, depends on the tone and elasticity of blood vessels, another name is “lower”.

What to do with high blood pressure, how to lower the pressure

A sharp increase in blood pressure is called a hypertensive crisis is not only a sharp increase in blood pressure to high numbers, but also an increase in all the main symptoms of the disease.

The reasons for the development of hypertensive crises are mental trauma and anxiety, negative emotions, changes in the weather (changes in atmospheric pressure, temperature and humidity).

Signs of hypertensive crisis

Often crises are accompanied by a sharp headache, dizziness, nausea, vomiting, loss of consciousness, visual disturbances (fog before the eyes, flashing “flies”). Most often, hypertensive crises are observed when, after improving health, the patient stops regularly taking antihypertensive drugs (drugs that lower blood pressure).

First of all, you need to calm down and lie down better. Open the window and provide fresh air. Strict bed rest must be observed. Sometimes it is easier when sitting.

If necessary, call an ambulance.

Before the arrival of the medical team, so-called distracting procedures should be carried out: put a mustard plaster on the occipital region and calf muscles, or make hot foot baths to drain blood to the legs.If a hypertensive crisis is accompanied by pain in the region of the heart, then validol or nitroglycerin can be taken under the tongue.

It is recommended to take additional doses of the medicine that the patient usually took. You can put pills under the tongue to lower blood pressure. As directed by a physician, the patient may receive injections of pressure-lowering drugs.

If, during a hypertensive crisis, the patient is in an agitated state, i.e.That is, is a neurovegetative crisis , then he is shown the introduction of sedatives, which relieve the agitated state.

In any case, it is necessary to lower blood pressure gradually, not to normal, but to a more comfortable state.

After the removal of the hypertensive crisis, they switch to routine medication treatment. If a hypertensive crisis has developed against the background of regular antihypertensive therapy, then it is necessary to reconsider the drugs of choice for the treatment of a particular patient.Only a doctor can do this. Therefore, after removing the crisis, you should seek help from your doctor.

Why do you need to measure blood pressure during pregnancy, as evidenced by high blood pressure

Hypertension is the most frequent complication of pregnancy and the cause of maternal and infant morbidity and mortality worldwide.

High blood pressure in early pregnancy is the most dangerous symptom.In this state, the walls of the blood vessels are very narrowed, and this interferes with the normal flow of oxygen and other nutrients from the blood to the forming fetus, which means that the physiological growth of the embryo slows down. Excessively high blood pressure can also cause miscarriage.

Also, hypertension can provoke a delay in fetal development, placental insufficiency, bleeding, chronic hypoxia (lack of oxygen), premature placental abruption.

High blood pressure during pregnancy can be a symptom of a complication such as gestosis is a condition that occurs in the second half of pregnancy and is manifested by a triad of symptoms: increased blood pressure, edema and the appearance of protein in the urine.

Pressurizing products

  1. alcoholic and carbonated drinks;
  2. spicy, smoked, salty foods and ready meals, canned food;
  3. Caffeine-rich foods: cocoa, coffee, strong tea;
  4. fish oil, fatty fish and meat, ice cream;
  5. cakes and pastries, which include butter cream, pastries;
  6. products with a high content of starchy substances: semolina, potatoes, white flour products;
  7. practically all offal: liver, brains, kidneys;
  8. seasonings and spices: pepper (black and red), raw onions, horseradish, mustard, cloves.

Salt. Table salt is known to trigger mechanisms in the body that lead to spasm of blood vessels. In addition, it is salt that makes a person feel thirsty, “forcing” him to consume more fluid, which leads to an increase in blood volume and an increase in blood pressure.

Pressure reducing products

  1. Products containing calcium – an active ingredient for lowering blood pressure, and dairy products are the best suppliers, since they contain vitamin D, which improves the absorption of calcium, cheese and yogurt, including; as well as green vegetables, broccoli, tofu, and almonds.
  2. Products containing potassium: oranges, bananas, dried apricots, tomatoes, baked potatoes, zucchini, tuna. Particular attention should be paid to mineral-rich oranges, pomegranates and kiwi.
  3. Products containing magnesium: green leaves of vegetables, beans, cereals (buckwheat, oatmeal, wheat), bran bread, almonds, walnuts, poppy seeds and beans, black currants, beets, carrots.