What is a Complete Blood Count (CBC) test. How does a CBC test help diagnose and monitor various health conditions. What are the key components measured in a CBC test. How can abnormal CBC results indicate different blood disorders.

The Importance of Complete Blood Count (CBC) in Diagnosing Health Conditions

A Complete Blood Count (CBC) is a crucial diagnostic tool used by healthcare professionals to assess overall health and detect a wide range of disorders. This comprehensive test provides valuable insights into the composition and quality of blood cells, offering a window into the body’s inner workings.

The CBC test measures several key components:

• White blood cell (WBC) count
• Red blood cell (RBC) count
• Platelet count
• Hemoglobin levels
• Hematocrit (fraction of blood composed of red blood cells)

Additionally, the test provides information on:

• Mean red blood cell volume (MCV)
• Mean hemoglobin amount per red blood cell (MCH)
• Mean hemoglobin concentration per red blood cell (MCHC)

Understanding the Seven Types of Blood Cells

The CBC test identifies and counts seven types of cells found in the blood:

1. Red blood cells
2. Neutrophils
3. Eosinophils
4. Basophils
5. Lymphocytes
6. Monocytes
7. Platelets

Each of these cell types plays a unique role in maintaining health and fighting disease. For example, basophils, though present in small numbers, are crucial in the body’s immune response. They release histamine and other chemicals that act on blood vessels when the immune system is triggered.

How does the CBC test help in diagnosing health issues?

The CBC test is invaluable in diagnosing and monitoring numerous diseases. It can reveal:

• Problems with fluid volume (e.g., dehydration)
• Blood loss
• Abnormalities in blood cell production, lifespan, and destruction
• Acute or chronic infections
• Allergies
• Clotting disorders

Common Blood Disorders Detected by CBC Tests

CBC tests can help identify various blood disorders, including:

Sickle Cell Anemia

Sickle cell anemia is an inherited blood disease characterized by abnormal hemoglobin production. This condition causes red blood cells to assume a crescent or sickle shape, which can lead to blockages in small blood vessels and various health complications.

Megaloblastic Anemia

Megaloblastic anemia is often associated with vitamin B-12 deficiency. In this condition, red blood cells appear large, dense, and oversized. A CBC test can reveal these abnormal cell characteristics, prompting further investigation into potential nutritional deficiencies.

Elliptocytosis

Elliptocytosis is a hereditary disorder affecting red blood cells. Instead of the typical round shape, red blood cells in this condition assume an elliptical form. This abnormality can be detected through microscopic examination of blood samples during a CBC test.

Spherocytosis

Another hereditary disorder, spherocytosis, causes red blood cells to be small and spherically shaped. These cells lack the light centers seen in normal, round red blood cells. This condition may be associated with mild anemia and can be identified through CBC testing.

The Role of CBC in Detecting Parasitic Infections

CBC tests can also help in identifying parasitic infections, such as malaria. Malarial parasites can be visible within red blood cells when examined under a microscope. They typically appear as dark bluish or orange-stained structures inside or outside the cells.

How does malaria affect blood cells?

Malaria parasites infect red blood cells, leading to their destruction and potentially causing severe anemia. The presence of these parasites can be detected during the microscopic examination phase of a CBC test, allowing for prompt diagnosis and treatment.

Abnormal Red Blood Cell Shapes and Their Significance

CBC tests can reveal various abnormal red blood cell shapes, each potentially indicating different health issues:

• Tear-drop shaped cells
• Target cells (cells resembling a bullseye)
• Sickle-shaped cells
• Cells with Pappenheimer bodies (iron-containing granules)

These abnormal shapes can be indicative of various conditions, from inherited disorders to acquired diseases. For instance, target cells may be seen in some forms of anemia or following the removal of the spleen (splenectomy).

The Multifaceted Functions of Blood in the Body

Blood plays numerous crucial roles in maintaining overall health:

• Transporting oxygen and nutrients to body tissues
• Removing waste and carbon dioxide
• Distributing hormones from endocrine organs to target tissues
• Regulating body temperature
• Maintaining normal pH levels in body tissues
• Forming clots to prevent excessive bleeding
• Preventing infections

How does blood contribute to the body’s defense mechanisms?

Blood contains various types of white blood cells that form a crucial part of the immune system. These cells help identify and neutralize pathogens, produce antibodies, and coordinate immune responses to protect the body from infections and diseases.

Interpreting CBC Results: What Do the Numbers Mean?

Understanding CBC results requires knowledge of normal ranges for each measured component. However, it’s important to note that “normal” can vary based on factors such as age, sex, and overall health status.

What are some common CBC abnormalities and their potential causes?

Some common abnormalities in CBC results include:

• High white blood cell count: May indicate infection, inflammation, or certain types of cancer
• Low red blood cell count: Could suggest anemia or blood loss
• High platelet count: Might indicate a bone marrow disorder or chronic inflammation
• Low platelet count: Could point to autoimmune disorders or certain medications

It’s crucial to interpret CBC results in conjunction with other clinical findings and under the guidance of a healthcare professional.

The Future of Blood Testing: Advances in CBC Technology

As medical technology continues to advance, CBC testing is becoming more sophisticated and informative. New techniques are being developed to provide more detailed analysis of blood components and detect even subtle abnormalities.

How are technological advancements improving CBC testing?

Recent innovations in CBC testing include:

• Automated cell counting systems for faster and more accurate results
• Flow cytometry for detailed analysis of cell populations
• Digital imaging technology for improved identification of abnormal cells
• Machine learning algorithms for pattern recognition in blood cell morphology

These advancements are enhancing the diagnostic capabilities of CBC tests, allowing for earlier detection of diseases and more personalized treatment approaches.

The Complete Blood Count test remains a cornerstone of medical diagnostics, providing invaluable insights into a patient’s health status. From detecting common anemias to identifying rare blood disorders and parasitic infections, the CBC continues to play a crucial role in guiding medical decisions and monitoring treatment efficacy. As technology evolves, we can expect even more sophisticated analysis techniques to emerge, further enhancing the power of this essential diagnostic tool.

Understanding the complexities of blood composition and function underscores the importance of regular health check-ups and appropriate use of diagnostic tests like the CBC. By staying informed about these vital aspects of our physiology, we can take proactive steps towards maintaining optimal health and well-being. As research in hematology and related fields progresses, our ability to interpret and act upon the wealth of information provided by CBC tests will undoubtedly improve, leading to more effective and personalized healthcare strategies.

CBC blood test Information | Mount Sinai

Complete blood count; Anemia – CBC

A complete blood count (CBC) test measures the following:

• The number of white blood cells (WBC count)
• The number of red blood cells (RBC count)
• The number of platelets
• The total amount of hemoglobin in the blood
• The fraction of the blood composed of red blood cells (hematocrit)

The CBC test also provides information about the following measurements:

• Mean red blood cell volume (MCV)
• Mean hemoglobin amount per red blood cell (MCH)
• The mean amount of hemoglobin relative to the size of the cell (hemoglobin concentration) per red blood cell (MCHC)

The complete blood count (CBC) is test, used to diagnose and monitor numerous diseases. It can reflect problems with fluid volume (such as dehydration) or loss of blood. It can show abnormalities in the production, life span, and destruction of blood cells. It can reflect acute or chronic infection, allergies, and problems with clotting. The CBC test identifies and counts the 7 types of cells found in the blood, red blood cell, neutrophil, eosinophil, basophil, lymphocyte, monocyte, and platelet.

Sickle cell anemia is an inherited blood disease in which the red blood cells produce abnormal pigment (hemoglobin). The abnormal hemoglobin causes deformity of the red blood cells into crescent or sickle-shapes, as seen in this photomicrograph.

This picture shows large, dense, oversized, red blood cells (RBCs) that are seen in megaloblastic anemia. Megaloblastic anemia can occur when there is a deficiency of vitamin B-12.

This photomicrograph shows one of the abnormal shapes that red blood cells (RBCs) may assume, a tear-drop shape. Normally, RBCs are round.

This photomicrograph shows normal red blood cells (RBCs) as seen in the microscope after staining.

Elliptocytosis is a hereditary disorder of the red blood cells (RBCs). In this condition, the RBCs assume an elliptical shape, rather than the typical round shape.

Spherocytosis is a hereditary disorder of the red blood cells (RBCs), which may be associated with a mild anemia. Typically, the affected RBCs are small, spherically shaped, and lack the light centers seen in normal, round RBCs.

Sickle cell anemia is an inherited disorder in which abnormal hemoglobin (the red pigment inside red blood cells) is produced. The abnormal hemoglobin causes red blood cells to assume a sickle shape, like the ones seen in this photomicrograph.

Basophils are a specific type of white blood cell. These cells are readily stained with basic dyes (this is where the name comes from). Note the dark grains inside the cellular fluid (cytoplasm) of this basophil. Basophils make up only a small portion of the number of white blood cells but are important parts of the body’s immune response. They release histamine and other chemicals that act on the blood vessels when the immune response is triggered.

Malarial parasites are visible within the red blood cells. They are stained a dark bluish color.

Malaria is a disease caused by parasites. This picture shows dark orange-stained malaria parasites inside red blood cells (a) and outside the cells (b). Note the large cells that look like targets; it is unknown how these target cells are related to this disease.

These crescent or sickle-shaped red blood cells (RBCs) are present with Sickle cell anemia, and stand out clearly against the normal round RBCs. These abnormally shaped cells may become entangled and block blood flow in the small blood vessels (capillaries).

This photomicrograph of red blood cells (RBCs) shows both sickle-shaped and Pappenheimer bodies.

These abnormal red blood cells (RBCs) resemble targets. These cells are seen in association with some forms of anemia, and following the removal of the spleen (splenectomy).

Blood transports oxygen and nutrients to body tissues and returns waste and carbon dioxide. Blood distributes nearly everything that is carried from one area in the body to another place within the body. For example, blood transports hormones from endocrine organs to their target organs and tissues. Blood helps maintain body temperature and normal pH levels in body tissues. The protective functions of blood include clot formation and the prevention of infection.

How the Test is Performed

A blood sample is needed.

How to Prepare for the Test

There is no special preparation needed.

How the Test will Feel

When the needle is inserted to draw blood, you may feel moderate pain. Some people feel only a prick or stinging. Afterward there may be some throbbing or slight bruising. This soon goes away.

Why the Test is Performed

A CBC is a commonly performed lab test. It can be used to detect or monitor many different health conditions. Your health care provider may order this test:

• If you are having symptoms, such as fatigue, weight loss, fever or other signs of an infection, weakness, bruising, bleeding, or any signs of cancer
• When you are receiving treatments (medicines or radiation) that may change your blood count results
• To monitor a long-term (chronic) health problem that may change your blood count results, such as chronic kidney disease

Normal Results

Blood counts may vary with altitude. In general, normal results are:

RBC count:

• Male: 4.7 to 6.1 million cells/mcL
• Female: 4.2 to 5.4 million cells/mcL

WBC count:

• 4,500 to 10,000 cells/mcL

Hematocrit:

• Male: 40. 7% to 50.3%
• Female: 36.1% to 44.3%

Hemoglobin:

• Male: 13.8 to 17.2 gm/dL
• Female: 12.1 to 15.1 gm/dL

Red blood cell indices:

• MCV: 80 to 95 femtoliter
• MCH: 27 to 31 pg/cell
• MCHC: 32 to 36 gm/dL

Platelet count:

• 150,000 to 450,000/dL

The examples above are common measurements for results of these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.

What Abnormal Results Mean

High RBC, hemoglobin, or hematocrit may be due to:

• A lack of enough water and fluids, such as from severe diarrhea, excessive sweating, or water pills used to treat high blood pressure
• Kidney disease with high erythropoietin production
• Low oxygen level in the blood for a long time, most often due to heart or lung disease, chronic carbon monoxide exposure, or living at a high altitude
• Polycythemia vera
• Smoking
• Use of testosterone

Low RBC, hemoglobin, or hematocrit is a sign of anemia, which can result from:

• Blood loss (either sudden, or from problems such as heavy menstrual periods over a long time)
• Bone marrow failure (for example, from radiation, infection, or tumor)
• Breakdown of red blood cells (hemolysis)
• Cancer and cancer treatment
• Certain long-term (chronic) medical conditions, such as chronic kidney disease, ulcerative colitis, or rheumatoid arthritis
• Iron deficiency
• Leukemia
• Long-term infections such as hepatitis
• Poor diet and nutrition, causing too little iron, folate, vitamin B12, or vitamin B6
• Multiple myeloma

A lower than normal white blood cell count is called leukopenia. A decreased WBC count may be due to:

• Alcohol abuse and liver damage
• Autoimmune diseases (such as systemic lupus erythematosus)
• Bone marrow failure (for example, due to infection, tumor, radiation, or fibrosis)
• Chemotherapy medicines used to treat cancer
• Disease of the liver or spleen
• Enlarged spleen
• Infections caused by viruses, such as mono or AIDS
• Medicines

A high WBC count is called leukocytosis. It can result from:

• Certain medicines, such as corticosteroids
• Infections
• Diseases such as lupus, rheumatoid arthritis, or allergy
• Leukemia
• Severe emotional or physical stress
• Tissue damage (such as from burns or a heart attack)

A high platelet count may be due to:

• Bleeding
• Diseases such as cancer or blood disease
• Iron deficiency
• Problems with the bone marrow

A low platelet count may be due to:

• Disorders where platelets are destroyed
• Pregnancy
• Enlarged spleen
• Bone marrow failure (for example, due to infection, tumor, radiation, or fibrosis)
• Chemotherapy medicines used to treat cancer

Risks

There is very little risk involved with having your blood taken. Veins and arteries vary in size from one person to another, and from one side of the body to the other. Taking blood from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight, but may include:

• Excessive bleeding
• Fainting or feeling lightheaded
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)

Considerations

RBCs transport hemoglobin which, in turn, carries oxygen. The amount of oxygen received by body tissues depends on the amount and function of RBCs and hemoglobin.

WBCs are mediators of inflammation and the immune response. There are various types of WBCs that normally appear in the blood:

• Neutrophils (polymorphonuclear leukocytes)
• Band cells (slightly immature neutrophils)
• T-type lymphocytes (T cells)
• B-type lymphocytes (B cells)
• Monocytes
• Eosinophils
• Basophils

Lin JC, Benz Jr. EJ. Approach to anemia in the adult and child. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 35.

Means RT. Approach to the anemias. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 149.

Vajpayee N, Graham SS, Bem S. Basic examination of blood and bone marrow. In: McPherson RA, Pincus MR, eds. Henry’s Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 31.

Last reviewed on: 10/16/2022

Reviewed by: Mark Levin, MD, Hematologist and Oncologist, Monsey, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

Red Blood Cell Count (RBC): Purpose, Procedure, and Preparation

Your RBC count may become too high or too low if you have certain health conditions, including nutritional deficiencies, erythrocytosis, and some chronic health conditions.

A red blood cell count is a blood test that your doctor uses to find out how many red blood cells (RBCs) you have. It’s also known as an erythrocyte count.

The test is important because RBCs contain hemoglobin, which carries oxygen to your body’s tissues. The number of RBCs you have can affect how much oxygen your tissues receive. Your tissues need oxygen to function.

If your RBC count is too high or too low, you could experience symptoms and complications.

If you have a low RBC count, symptoms could include:

• fatigue
• shortness of breath
• dizziness, weakness, or lightheadedness, particularly when you change positions quickly
• increased heart rate
• headaches
• pale skin

If you have a high RBC count, you could experience symptoms such as:

• fatigue
• shortness of breath
• joint pain
• tenderness in your palms or soles of your feet
• itching skin, particularly after a shower or bath
• sleep disturbance

If you experience these symptoms your doctor can order an RBC count.

According to the Association for Clinical Biochemistry and Laboratory Medicine, the test is almost always part of a complete blood count (CBC). A CBC measures all components in the blood, including:

• red blood cells
• white blood cells
• hemoglobin
• hematocrit
• platelets

Your hematocrit is the volume of red blood cells in your body. A hematocrit test measures the ratio of RBCs in your blood.

Platelets are small cells that circulate in the blood and form blood clots that allow wounds to heal and prevent excessive bleeding.

Your doctor may order the test if they suspect you have a condition that affects your RBCs, or if you show symptoms of low blood oxygen. These could include:

• bluish discoloration of the skin
• confusion
• irritability and restlessness
• irregular breathing

A CBC will often be part of a routine physical exam. It can be an indicator of your overall health. It may also be performed before a surgery.

If you have a diagnosed blood condition that may affect RBC count, or you’re taking any medications that affect your RBCs, your doctor may order the test to monitor your condition or treatment. Doctors can use CBCs to monitor conditions like leukemia and infections of the blood.

An RBC count is a simple blood test performed at your doctor’s office. A healthcare professional will draw blood from your vein, usually on the inside of your elbow. They will then:

1. clean the puncture site with an antiseptic
2. wrap an elastic band around your upper arm to make your vein swell with blood
3. gently insert a needle into your vein and collect the blood in an attached vial or tube
4. remove the needle and elastic band from your arm

After collecting your blood sample, your doctor’s office will send it to a laboratory for analysis.

There’s typically no special preparation needed for this test. But you should tell your doctor if you’re taking medications. These include any over-the-counter (OTC) drugs or supplements.

Your doctor will be able to tell you about any other necessary precautions.

As with any blood test, there’s a risk of bleeding, bruising, or infection at the puncture site. You may feel moderate pain or a sharp pricking sensation when the needle enters your arm.

RBC ranges are measured in terms of cells per microliter (µL). Normal ranges for RBC differ based on age and sex assigned at birth.

	Normal RBC range (million cells/µL)
Adult, assigned female at birth	4.2 – 5.4
Adult, assigned male at birth	4.7 – 6.1
Child, 1 – 18 years	4.0 – 5.5
Infant, 6 – 12 months	3.5 – 5.2
Infant, 2 – 6 months	3.5 – 5.5
Infant, 2 – 8 weeks	4.0 – 6.0
Newborn	4.8 – 7.1

These ranges may vary depending on the laboratory or doctor. Ranges may also differ for those who are pregnant.

If your number of RBCs is lower than normal, you have anemia. This can be caused by a decrease in RBC production or by the destruction or loss of RBCs. There are many possible causes for anemia.

Nutritional Deficiency

Iron-deficiency anemia is the most common type of anemia, but lack of other nutrients can also cause your RBC count to decrease. These include:

• copper
• folate (vitamin B9)
• vitamin B6
• vitamin B12

Bone marrow failure

In rare cases, your bone marrow might stop making new blood cells. This is caused aplastic anemia.

Aplastic anemia might be an autoimmune disorder. Certain drugs, viruses, toxins, or radiation may also cause aplastic anemia.

Hemolysis

Hemolysis is the destruction of red blood cells. Common causes of hemolysis include:

• autoimmune reaction to blood transfusion
• infection
• inherited conditions, like sickle cell anemia

Chronic conditions

Underlying health conditions that cause inflammation may affect the way your body processes erythropoietin (EPO). EPO is a hormone that causes bone marrow to produce RBCs.

EPO is produced in the kidneys. If you have chronic kidney disease, you might produce less EPO than normal.

Other chronic conditions that may cause a low RBC count include, but are not limited to:

• autoimmune diseases, like rheumatoid arthritis or lupus
• infections, like HIV or tuberculosis
• cancers, like leukemia or multiple myeloma
• IBD, including Crohn’s disease and ulcerative colitis

Other conditions

Other possible reasons for a lower than normal RBC count include:

• internal or external bleeding
• pregnancy
• thyroid disorders

Medications

Certain drugs can also lower your RBC count, especially:

• chemotherapy drugs
• chloramphenicol, which treat bacterial infections
• quinidine, which can treat irregular heartbeats
• hydantoins, traditionally used to treat epilepsy and muscle spasms

If your RBC count is higher than normal, you have erythrocytosis. This causes your blood to be thicker than normal and can increase your risk of blood clots.

Primary erythrocytosis

Primary erythrocytosis is when your own body causes you to produce more RBCs. This is usually due to a problem with cells in your bone marrow. The condition is often inherited.

One such condition is polycythemia vera, a bone marrow disease that causes overproduction of RBCs and is associated with a genetic mutation.

Secondary erythrocytosis

Secondary erythrocytosis is when an external factor increases your RBC count. This could be due to a disease, drug, or another cause.

Some medical conditions that can cause a high red blood cell count include:

• congenital heart disease
• respiratory disorders, like COPD, pulmonary fibrosis, or sleep apnea
• renal disorders, such as cysts or kidney disease
• certain tumors, like renal cell carcinoma or hepatocellular carcinoma

Certain drugs can increase your RBC count, including:

• gentamicin, an antibiotic used to treat bacterial infections in the blood
• methyldopa, often used to treat high blood pressure
• performance-enhancing drugs, like anabolic steroids or protein injections
• diuretics

Tell your doctor about any medications you take.

Other potential reasons for an elevated RBC count include:

• cigarette smoking
• living at a higher altitude
• dehydration
• blood doping

Blood cancers can affect the production and function of red blood cells. They can also result in unusual RBC levels.

Each type of blood cancer has a unique impact on RBC count. The three main types of blood cancer are:

• leukemia, which impairs the bone marrow’s ability to produce platelets and red blood cells
• lymphoma, which affects the white cells of the immune system
• myeloma, which prevents normal production of antibodies

Your doctor will discuss any abnormal results with you. Depending on the results, they may need to order additional tests.

These can include blood smears, where a film of your blood is examined under a microscope. Blood smears can help detect abnormalities in the blood cells (such as sickle cell anemia), white blood cell disorders such as leukemia, and bloodborne parasites like malaria.

A bone marrow biopsy can show how the different cells of your blood are made within your bone marrow. Diagnostic tests, such as ultrasounds or electrocardiograms, can look for conditions affecting the kidneys or heart.

Treatment for a low RBC count

All types of anemia require treatment. Your treatment will depend on what’s causing your anemia.

• Iron deficiency. You can take iron supplements or receive iron infusions through your veins.
• Vitamin deficiency. You can take vitamin supplements.
• Bone marrow failure. Your doctor may prescribe certain medications. If medications don’t help, you may need a bone marrow transplant.
• Chronic conditions. Your doctor will usually focus on treating the underlying condition. Sometimes, they may prescribe an EPO-stimulating agent.
• Blood loss. A blood transfusion can bring in more RBCs to your body.

Treatment for a high RBC count

If you have erythrocytosis, you may need a regular phlebotomy. This removes a small amount of blood from your body in order to lower your RBC count.

If phlebotomies don’t work, your doctor may prescribe hydroxyurea (Hydrea or Droxia) to reduce your RBC count.

You may also need aspirin to help with potential blood clots.

Lifestyle changes can affect your RBC count. Some changes that can help increase your RBC count include:

• maintaining a healthy diet and avoiding vitamin deficiencies
• exercising regularly, which requires the body to use up more oxygen
• avoiding aspirin
• reducing alcohol consumption

If you need to decrease your RBC count, the following lifestyle changes may help:

• reducing the amount of iron and red meat that you consume
• drinking more water
• avoiding diuretics, such as drinks containing caffeine or alcohol
• quitting smoking

Dietary changes

Dietary changes can play a major part in home treatment by managing your RBC count.

You may be able to increase your RBC with the following dietary changes:

• adding iron-rich foods (such as meat, fish, poultry, tofu), as well as dried beans, peas, and leafy green vegetables (such as spinach) to your diet
• increasing copper in your diet with foods like shellfish, poultry, and nuts
• getting more vitamin B12 with foods like eggs, meats, and fortified cereals

An RBC count that is either too high or too low can have serious health complications.

There is much you can do on your own to manage your RBC count, staring with a balanced diet and regular exercise. If you have blood cancers or chronic conditions that can affect RBC count, these lifestyle and dietary habits may be especially important.

Consult a doctor if you experience fatigue or shortness of breath. These are often symptoms of an abnormal RBC count.

Clinical blood test with leukocyte formula

General (clinical) blood test with the formula is the main laboratory test most often prescribed for any pathological process. A blood test with a formula includes determining the number of all blood cells (erythrocytes, leukocytes, platelets), determining the content of hemoglobin, hematocrit, erythrocyte indicators (MCV, MCH, MCHC).

When is a formula clinical blood test usually ordered?

This study is prescribed, in preparation for hospitalization and planned surgical interventions, with annual medical examinations, repeatedly during pregnancy, in children before any vaccination.

For any disease, a general blood test with a leukocyte formula is a study that provides the necessary information about the current condition of the patient. The presence of anemia and hematological diseases, the severity of inflammation and the response of the body’s immune system, indicators of the allergic process and possible signs of helminthic invasion – this information can be obtained from a clinical blood test with a formula.

What exactly is determined in the process of analysis?

Erythrocytes (RBC, red blood cells, “red blood cells”) – non-nuclear blood cells containing hemoglobin. The shape of erythrocytes in the form of a biconcave disk provides an increase in their surface area and an increase in the possibilities of gas exchange; gives plasticity when passing through the capillaries. The main function of erythrocytes is to transport oxygen from the lungs to tissues and carbon dioxide from tissues to the lungs. Determination of the number of erythrocytes is of the most important diagnostic value in the diagnosis of anemia in combination with the determination of hemoglobin, hematocrit, erythrocyte indices.

Hemoglobin (Hb, HGB, hemoglobin) is the main component of erythrocytes, the structure consists of protein (globin) and iron (heme), the main function is the transport of oxygen and carbon dioxide and their exchange between the lungs and tissues of the body. The level of hemoglobin depends on gender, age, altitude above sea level (inhabitants of high mountains have higher hemoglobin), smoking. Hemoglobin is measured in grams per 1 ml of blood, therefore, when assessing the level of hemoglobin, you need to pay attention to hematocrit. An increase in hematocrit (usually associated with dehydration) can falsely increase the concentration of hemoglobin.

Hematocrit (Ht, Hematocrit) – the percentage of red blood cells in the total blood volume, reflects hemoconcentration. The determination of hematocrit is used to assess the degree of anemia, the calculation of erythrocyte indices. Changes in hematocrit do not always correlate with changes in the total number of red blood cells, so the hematocrit value is difficult to interpret immediately after acute blood loss or blood transfusion.

MCV (Mean Cell volume) – the average volume of an erythrocyte, a calculated indicator. The mean volume of an erythrocyte is used in the differential diagnosis of anemia. According to the MCV value, normocytic anemias are distinguished (MCV 80-100 fl in adults and children from 5 years old), microcytic (MCV less than 80 fl) and macrocytic (more than 100 fl). In the presence of erythrocytes of different shapes (anisocytosis) or a large number of erythrocytes with an altered form, MCV may not be informative enough.

MCH (Mean Cell Hemoglobin) – the average content of hemoglobin in an erythrocyte (in 1 cell). The calculated indicator, according to the clinical value of the MSI, is similar to the color indicator, but is more reliable, and is calculated in absolute units (pg). Used in the differential diagnosis of anemia. Based on the MSI index, normochromic, hypochromic and hyperchromic anemias are distinguished.

MCHC (Mean Cell Hemoglobin Concentration) – the average concentration of hemoglobin in red blood cells. An indicator of the degree of saturation of an erythrocyte with hemoglobin. This is a concentration index that does not depend on cell volume. MCHC is a sensitive indicator reflecting changes in hemoglobin formation; relevant in the diagnosis of iron deficiency anemia, thalassemia, some types of hemoglobinopathies.

Rel. red cell distribution width (RDW, Red cell Distribution Width) – a measure of the difference in red blood cells by volume. In the blood of a healthy person, erythrocytes differ slightly, and the RDW indicator borders within 12-15%. RDW above normal reflects the heterogeneity (heterogeneity) of erythrocytes (degree of anisocytosis). Used in the differential diagnosis and monitoring of anemia treatment.

Platelets (PLT, Platelets) are blood cells involved in clotting. They are non-nuclear cytoplasmic fragments of their predecessors – megakaryocytes formed in the bone marrow. The average lifespan in the bloodstream is 10 days. In a calm state, platelets have a disc-shaped shape, when activated, they become spherical and form special outgrowths – pseudopodia, thanks to which they connect with each other and stick to the vascular wall (the ability to aggregate and adhere), while releasing biologically active substances that contribute to the restoration of the vascular wall when damaged (angiotrophic function). Platelets provide stop bleeding in small vessels (platelet-vascular hemostasis).

Determining the number of platelets is used to assess the risk of developing thrombotic and hemorrhagic complications, in hemorrhagic syndrome, in a comprehensive examination of the blood coagulation system, and for monitoring during chemotherapy. Fluctuations in the level of platelets during the day are possible.

Leukocytes (WBC, White Blood Cell) are immunity cells, their ratio and maturity is determined in the leukocyte formula.

In the normal leukocyte formula, you can see the following populations of cells and their percentage: neutrophils, monocytes, lymphocytes, basophils, eosinophils. Normally, these cells are present in the blood in relatively stable amounts. Their ratio depends on age. In children under 5-6 years of age, lymphocytes predominate in the blood formula, in adults there is a clear predominance of neutrophils.

What do the test results mean?

White blood cells: an increased number of white blood cells (leukocytosis) can be a sign of infection (both bacterial and viral, a marker of current inflammation (including autoimmune or allergic), a sign of a hematological disease.

A decrease in the level of leukocytes (leukopenia) may be associated with a severe infection (up to sepsis), with the toxic effect of medications taken, and with bone marrow damage.

Neutrophils: An increase in the number of neutrophils may be associated with bacterial infection, inflammation, trauma, severe stress or early postoperative period.

A decrease in the number of neutrophils is usually associated with a reaction to drugs, autoimmune diseases, immunodeficiency states, and bone marrow damage.

Lymphocytes: An increase in the number of lymphocytes (lymphocytosis) can be observed in acute viral infections, infections of the herpes group (EBV infection, CMV infection, etc.), in some bacterial infections (whooping cough, tuberculosis intoxication), chronic inflammatory diseases ( such as ulcerative colitis), lymphocytic leukemia.

A decrease in the number of lymphocytes (lymphopenia) is often associated with autoimmune diseases, chronic viral infections (HIV, viral hepatitis), effects on the bone marrow, and taking corticosteroids.

Monocytes: Monocytes may be elevated in long-term chronic infections (tuberculosis, fungal infections), connective tissue diseases and vasculitis, monocytic or myelomonocytic leukemia.

A short-term decrease in the number of monocytes has no diagnostic value. A long-term decrease in the number of monocytes, combined with other pathology in the blood test, may be associated with aplastic anemia or bone marrow damage.

Eosinophils: An increase in the number of eosinophils may be associated with parasitic infestations, asthma, allergies, inflammatory diseases of the gastrointestinal tract.

The absence of eosinophils in the blood formula may be normal and has no clinical significance.

Basophils: An increase in the number of basophils can be observed in rare allergic reactions, chronic inflammatory diseases, renal failure (uremia).

The decrease or absence of basophils has no clinical significance.

Platelets: in addition to true thrombocytopenia (low platelet count), the rare occurrence of EDTA-dependent thrombocytopenia may occur. Currently, to perform a general blood test, blood is taken in test tubes with an anticoagulant – EDTA. In rare cases, the interaction of the patient’s blood with EDTA leads to aggregation (sticking) of platelets among themselves and the inability to accurately calculate their number. In this case, the analyzer is not able to isolate these cells and accurately count them, which can lead to a falsely low number of platelets in the blood. If a low platelet count is detected by the analyzer, the laboratory conducts a microscopy of the blood smear and gives a conclusion about the presence of platelet aggregates in the smear.

Normal test completion time

Usually the result of a clinical blood test with a formula can be obtained within 1-2 days

Is special preparation required for analysis?

Special preparation is not required. You can take the test 3 hours after eating or on an empty stomach. In infants, blood is usually taken before the next feeding.

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How a blood test is done and what the results mean: a detailed guide

Contents

• 1 CBC: what it shows and how it is done
  • 1.1 How is CBC done?
    • 1.1.1 Preparation for analysis
    • 1.1.2 Blood donation
    • 1.1.3 Test results
  • s
• 1.3 Selection
• 1.4 How is a clinical blood test performed and what do the results show?
  • 1.4.1 Sending blood to the laboratory:
• 1.5 How is the CBC done and what does the CBC show?
• 1.6 Hemoglobin testing:
• 1.7 How is the CBC done and what does it show? 9010 6
• 1.7 .1 White blood cell count:

1.8 Platelet test:

1.9 Glucose test:

1.10 Blood protein test:

1.11 Cholesterol test:

1.12 CBC values ​​and their meaning:

• 1.12.1 Erythrocytes (RBC index)
• 1.12.2 Leukocytes (Leukocyte index)

901 07 1. 12.3 Platelets (Platelet index)

1.13 Related videos:

1.14 Q&A:

• • 1.14.0.1 What is a CBC?
  • 1.14.0.2 How is a CBC performed?
  • 1.14.0.3 What parameters are measured in a clinical blood test?
  • 1.14.0.4 What diseases does a clinical blood test show?
  • 1.14.0.5 Do I need to be on an empty stomach before a CBC?
  • 1.14.0.6 What are the limitations after CBC?

Find out how a clinical blood test is performed and what indicators should be considered in the analysis. We will analyze in detail the results and their significance for the health of the body.

Clinical blood test is one of the main methods for diagnosing the presence of diseases in the body. It is carried out in order to assess the state of the blood, reflecting the work of various systems and organs of the body. All it takes to perform a blood test is to take a small amount of blood from a vein and send it to the laboratory.

CBC results can show levels of hemoglobin, white blood cells, platelets, sugar, and other blood components. High or low levels of these components may indicate diseases. For example, an elevated white blood cell count may indicate an infection in the body, and a low hemoglobin level may indicate the presence of anemia.

CBC can also be used to monitor the performance of certain drugs. For example, white blood cell counts may be elevated as a result of certain antibiotics. Carrying out a blood test is an important step in the prevention and treatment of various diseases, and also allows you to quickly determine the cause of various symptoms.

How is a CBC performed?

Preparing for the test

You must abstain from food for at least 8 hours before donating blood to rule out the effect of food on the test results. On the day of the test, you should not take drugs and alcohol, which can distort the results of the analysis.

It is also necessary to measure the body temperature before the analysis and report it to the laboratory assistant, as an elevated temperature can distort the results of the analysis.

Blood donation

Blood for analysis is taken from a vein in the elbow using a special needle. Before blood sampling, the site of the vein is treated with an antiseptic to exclude the possibility of infection.

Typically, approximately 10 ml of blood is taken for analysis and collected in a special tube. The blood sample is then sent to the laboratory for analysis.

Test results

Test results are usually available within a few days. They are a table in which blood parameters are indicated, such as the number of red blood cells, hemoglobin, white blood cells, etc., as well as their average values ​​are normal.

To evaluate the results of the analysis, it is necessary to pay attention to deviations from the norm in any direction. This may indicate any diseases that require additional examination and treatment.

How it is done and what the results of a clinical blood test show

Preparing for the test

Before taking a blood test, you need to follow some recommendations so that the results are as accurate and reliable as possible.

• 10-12 hours before the test, you must refuse food and alcohol;
• Do not smoke or drink alcoholic beverages 1-2 hours before testing;
• It is not recommended to engage in physical activity and experience emotional stress before the analysis;
• If the patient is taking any medications, it is imperative to discuss this issue with the doctor.

Also, before taking the test, you must set the exact day and time when you can pick up the results and a personal sheet with the patient’s data.

Blood sampling

Blood sampling for clinical analysis is carried out in a special place – the laboratory of a medical institution. Usually selection is carried out in the morning and after a 12-hour fast. If the patient is being treated in a hospital, then blood sampling is carried out directly in the ward according to the rules of asepsis and antisepsis.

Before sampling, it is necessary to monitor the quality of the material, because affects not only the results, but also the life and health of the patient. For analysis of blood taken for analysis, it is recommended to use vacuum systems: selection of several types of analyzes in a single container, ensuring a minimum amount of blood at a high sampling rate, etc.

Before blood sampling, people are often asked to drink water and get out of stress for at least 10-15 minutes. This is necessary so that the patient’s pressure is not elevated and the blood does not oxidize. Wide swabs disinfect the skin at the site of future selection. Then, the nurse perforates the vein, inserts a needle into the blood vessel, and draws the volume of blood needed for analysis.

How is it carried out and what do the results of a clinical blood test show?

Blood donation to the laboratory:

Before starting a clinical blood test, you must donate blood for analysis. To do this, the patient must go to a medical facility where he will be tested. Blood is taken from a vein or a finger.

Further, the collected blood is sent to the laboratory for further analysis. During the transfer phase, the sample must be properly stored and transported. It is important to observe certain temperature regimes and delivery times in order to avoid distorting the results.

Upon arrival at the laboratory, the blood is specially prepared before being processed. It is centrifuged to separate the components, and then each of them is analyzed. They study the indicators of hemoglobin, leukocytes, platelets and other blood components.

The results of a clinical blood test allow you to evaluate the general health of the patient and detect any deviations from the normal values. They can help diagnose various diseases such as anemia, infectious diseases, bleeding disorders, etc.

How is it carried out and what the results of a clinical blood test show: determination of the number of red blood cells

The number of red blood cells is one of the important indicators of a complete blood count. It reflects the number of red blood cells that carry oxygen from the lungs to the organs and tissues of the body.

To determine the number of red blood cells, blood is taken from the patient’s vein and placed in a test tube with an anticoagulant. The test tube is placed in a special blood analyzer, which automatically counts the number of red blood cells in one microliter of blood.

Red cell count may be higher or lower than normal. High rates may be associated with dehydration, cardiovascular disease, smoking, alcoholism. Low values ​​can be associated with blood loss, iron deficiency, bone marrow diseases, etc. cells.

Hemoglobin test:

Hemoglobin is the protein component of red blood cells that carries oxygen from the lungs to human organs and tissues. It also helps the blood carry carbon dioxide from the tissues back to the lungs, where it is excreted from the body. Measurement of hemoglobin levels is an important component of a clinical blood test and helps doctors detect the presence of diseases and evaluate the effectiveness of treatment.

The normal level of hemoglobin depends on the sex, age and health of the person. Adult men are usually recommended to have a hemoglobin level between 13.5 and 17.5 g/dl, and for women between 12 and 15.5 g/dl. During pregnancy, hemoglobin levels may drop slightly, which is normal.

A low hemoglobin level may indicate anemia, which occurs when the blood does not contain enough red blood cells or when they cannot perform their functions properly. Excessive hemoglobin levels can either indicate a disorder in the blood cells or fluid ingestion, primary or secondary erythrosis, or reduced oxygen levels.

Some causes of hemoglobin damage

Reasons for low hemoglobin
Reasons for high hemoglobin

Iron deficiency Chronic diseases such as HIV / AIDS, diabetes and cancer Injury or blood loss	Breathe due to mountain altitude Chronic obstructive pulmonary disease (COPD) Poly Cythemia (too many cells blood)

How it is carried out and what the results of a clinical blood test show

Determining the number of leukocytes:

Leukocytes are one of the main components of the biological immune system that fight infections and other pathogens. Their number in the blood may indicate the presence or absence of inflammatory and infectious processes in the body.

A general clinical blood test is performed to determine the number of leukocytes. In this case, a small amount of blood is taken from the patient’s vein and subjected to a special study in the laboratory.

The results of the analysis are numerical values ​​that indicate the number of leukocytes in 1 microliter of blood. The normal number of leukocytes in the blood of an adult is from 4 to 10 thousand in 1 microliter of blood.

An increase or decrease in the number of leukocytes in the blood may indicate the presence of diseases or processes occurring in the body. For example, an elevated white blood cell count can be a sign of inflammation, infections, allergic reactions, and other conditions. A decrease in the number of white blood cells may indicate disorders in the immune system, as well as chemotherapy or radiation.

Platelet testing:

Platelets or “platelets” play an important role in the blood clotting process. Their amount in the blood and their ability to clot can be assessed using a clinical blood test.

Evaluation of platelets includes measuring the number of their cells per unit volume of blood and assessing their shape. The platelet count may be elevated in some conditions, such as thrombocytopenia, anemia, or leukemia. A low platelet count may be associated with conditions such as thrombocytopenia or hemophilia.

Platelet shape evaluation includes measurement of size, shape and degree of carbon fiber. Abnormalities in shape can also indicate the presence of medical conditions such as anemia or von Willebrand disease.

Measuring glucose:

Glucose is a sugar that is one of the most important sources of energy for body cells. A person’s blood glucose level is determined using a blood test.

Blood glucose should normally be between 70 and 100 mg/dl. If the blood glucose level is higher, then this may indicate the presence of diabetes. If the glucose level is too low, it can lead to hypoglycemia.

A blood glucose test is performed to determine the level of glucose in the blood. During a blood test, a small amount of blood is usually taken from a vein. The blood is then placed in a test tube and sent to a laboratory for analysis.

The results of a blood glucose test can indicate the presence of diabetes, and can help the doctor determine the effectiveness of diabetes treatment and adjust the dose of insulin if necessary.

Normal blood glucose values ​​

Glucose level, mg/dL
Glucose tolerance

9028 3

Less than 70	Hypoglycemia
70 – 100	Normal
101 — 125	Prediabetic
Over 126	Diabetes

Study protein level in the blood:

One of the important parameters determined by a clinical blood test is the level of protein in the blood serum. Proteins are critical to the functioning of the body and are the building blocks of cells, tissues and organs.

Blood protein testing is used to diagnose various diseases such as inflammation, infectious diseases, cancer and other pathologies. An increase or decrease in the level of protein in the blood may indicate the presence of a disease and control the dynamics of its development.

Blood protein testing requires blood drawn from a vein. The results of the analysis can be presented in tabular form, which displays the total amount of proteins, as well as their fractions. It is important to note that protein levels may vary depending on the age, sex and health of the patient.

• Albumin is the most abundant protein in the blood and is made by the liver. Its level can change in response to various physiological processes and diseases, such as obesity, liver disease, kidney disease, and others.
• globulins are a group of proteins that perform various functions in the body, such as protecting against infection and transporting hormones. Their level can change in various diseases, such as rheumatoid arthritis, systemic lupus erythematosus and others.

The study of the level of protein in the blood allows you to diagnose various diseases and monitor their course. However, for the correct interpretation of the results, many factors must be taken into account, such as the age, sex and health of the patient.

Determination of cholesterol level:

One of the most important indicators in the clinical analysis of blood is the level of cholesterol. Cholesterol is a fatty substance essential for many biological processes in the body. However, high cholesterol can lead to serious diseases such as atherosclerosis and heart disease.

When performing a clinical blood test, cholesterol levels are usually measured together with high-density lipoprotein (HDL-C) and low-density lipoprotein (LDL-C) levels. HDL-C is considered “good” cholesterol, which protects the heart and blood vessels, while LDL-C, on the contrary, increases the risk of heart disease.

The normal level of cholesterol in the blood depends on the age and sex of the person. However, in general, healthy adults are advised to monitor their LDL-C and HDL-C levels. A good HDL-C level is over 60 mg/dL, and LDL-C should not exceed 130 mg/dL.

If the level of cholesterol in the blood is high, it is recommended to change lifestyle and diet. In some cases, medications may be needed to lower LDL-C and increase HDL-C.

Clinical blood test indicators and their meaning:

Erythrocytes (Erythrocyte index)

This group of indicators evaluates the quantity and quality of erythrocytes in the blood. Red blood cells are responsible for the transport of oxygen and carbon dioxide in the body. The composition of the erythrocyte index includes:

• Red blood cells
• Hemoglobin
• Hematocrit (volume of blood occupied by red blood cells)

Red blood cell count may indicate the presence of anemia or blood disorders. A high hematocrit may indicate dehydration.

Leukocytes (Leukocyte Index)

Leukocytes play a key role in protecting the body from infection and disease. The leukocyte index assesses the quantity and quality of leukocytes in the blood. It consists of:

• Leukocytes
• Neutrophils
• Lymphocytes
• Eosinophils
• Monocytes

The level of leukocytes may indicate the presence of an inflammatory process or infection in the body. A high level of neutrophils or eosinophils may indicate an allergy or an autoimmune disease.

Platelets (Platelet Index)

Platelets are responsible for blood clotting and preventing bleeding. The platelet index evaluates the quantity and quality of platelets in the blood. It consists of:

• Platelets
• Mean platelet count
• Mean platelet hemoglobin

Related videos:

Q&A:

What is a CBC?

A CBC is a medical test that measures various parameters of your blood such as red and white cells, platelets, hemoglobin, and other components. This test allows you to diagnose various diseases such as anemia, infections, multiple myeloma and other conditions.

How is a clinical blood test performed?

CBC requires a small sample of blood to be taken from a vein in your forearm or finger. The blood is placed in a test tube and sent for analysis. The procedure takes only a few minutes and does not require special preparation. However, some rules may need to be followed before the test, such as not eating or drinking for a few hours before the test, which will be communicated to you by your doctor or nurse.

What parameters are measured in a clinical blood test?

CBC measures various parameters such as red and white cell counts, hemoglobin levels, platelets and other components. In addition, parameters such as the erythrocyte sedimentation rate (ESR) and the content of certain proteins in the blood can be measured.

What diseases does a clinical blood test show?

CBC can detect various conditions such as anemia, leukemia, infections, allergic reactions, and other conditions.