What is a platelet count test. How does it diagnose thrombocytopenia. What are the symptoms of low and high platelet counts. When should you get tested for platelet disorders. How is the test performed and interpreted.

Understanding Platelets and Their Function in Blood Clotting

Platelets, also known as thrombocytes, are tiny cell fragments that play a crucial role in blood clotting. These microscopic components circulate in our bloodstream, ready to spring into action when needed. But what exactly do platelets do?

Platelets are essential for hemostasis, the process that stops bleeding. When a blood vessel is damaged, platelets rush to the site of injury, adhering to the vessel wall and to each other. This forms a platelet plug, which is the first step in stopping blood loss. Platelets also release chemicals that activate the coagulation cascade, leading to the formation of a more stable fibrin clot.

The Importance of Platelet Count

Maintaining an adequate number of platelets is crucial for proper blood clotting. A normal platelet count ranges from 150,000 to 450,000 platelets per microliter of blood. When the count falls below or rises above this range, it can lead to various health issues.

• Too few platelets (thrombocytopenia) can result in excessive bleeding
• Too many platelets (thrombocytosis) can increase the risk of blood clots

Given the vital role platelets play in our body’s ability to control bleeding and prevent excessive clotting, monitoring platelet count becomes essential in many medical situations.

The Platelet Count Test: Purpose and Procedure

A platelet count test is a diagnostic tool used to assess the number of platelets in a person’s blood. This test is crucial for evaluating a patient’s risk of bleeding or clotting disorders. But how is this test performed?

The platelet count test is typically part of a complete blood count (CBC), which analyzes various components of blood. Here’s a step-by-step breakdown of the procedure:

1. A healthcare professional draws a small blood sample from a vein in your arm
2. The sample is sent to a laboratory for analysis
3. An automated machine counts the platelets in the sample
4. Results are reported as the number of platelets per microliter of blood

In some cases, particularly when automated results are abnormal or inconclusive, a manual count using a microscope may be performed. This method, known as a peripheral blood smear, allows for a more detailed examination of platelet number and appearance.

When Is a Platelet Count Test Necessary?

There are several scenarios where a healthcare provider might recommend a platelet count test:

• As part of routine health screenings
• To diagnose or monitor platelet disorders
• Before surgical procedures to assess bleeding risk
• To monitor the effects of certain medications or treatments
• When a patient shows symptoms of abnormal bleeding or clotting

Regular monitoring of platelet counts is particularly important for individuals with known blood disorders or those undergoing treatments that can affect platelet production, such as chemotherapy.

Thrombocytopenia: When Platelet Counts Are Too Low

Thrombocytopenia is a condition characterized by an abnormally low platelet count. But what exactly constitutes “low,” and what are the implications of this condition?

A platelet count below 150,000 per microliter is considered low. However, the severity and risk of complications increase as the count drops further. Mild thrombocytopenia (100,000-150,000 platelets/μL) often doesn’t cause symptoms, while severe thrombocytopenia (below 50,000 platelets/μL) can lead to spontaneous bleeding.

Symptoms of Thrombocytopenia

Recognizing the signs of low platelet count is crucial for early diagnosis and treatment. Common symptoms include:

• Easy bruising
• Petechiae (small, round, reddish-purple spots on the skin)
• Prolonged bleeding from cuts
• Nosebleeds or bleeding gums
• Heavy menstrual periods
• Blood in urine or stool

In severe cases, internal bleeding can occur, which may manifest as headaches, dizziness, or abdominal pain. If you experience any of these symptoms, especially if they’re persistent or severe, it’s important to consult a healthcare provider promptly.

Causes and Risk Factors for Low Platelet Count

Thrombocytopenia can result from various factors affecting platelet production, destruction, or distribution in the body. Understanding these causes can help in prevention and management of the condition.

Common Causes of Thrombocytopenia

• Immune thrombocytopenia (ITP): The immune system mistakenly attacks and destroys platelets
• Bone marrow disorders: Conditions like leukemia or aplastic anemia can impair platelet production
• Viral infections: Certain viruses, including HIV and hepatitis C, can affect platelet count
• Medications: Some drugs, particularly chemotherapy agents, can suppress platelet production
• Pregnancy: Gestational thrombocytopenia can occur in late pregnancy
• Alcohol abuse: Excessive alcohol consumption can suppress bone marrow function

Risk factors for developing thrombocytopenia include a family history of bleeding disorders, certain medical conditions, and exposure to toxic chemicals. Additionally, age can play a role, with some forms of thrombocytopenia being more common in specific age groups.

Thrombocytosis: When Platelet Counts Are Too High

While low platelet counts are often a concern, high platelet counts, known as thrombocytosis, can also pose significant health risks. But what exactly constitutes a high platelet count, and what are its implications?

Thrombocytosis is typically diagnosed when the platelet count exceeds 450,000 per microliter. However, the severity and associated risks can vary depending on the underlying cause and the degree of elevation. Mild thrombocytosis may not cause any symptoms, while severe cases can lead to serious complications.

Symptoms and Risks of High Platelet Count

The symptoms of thrombocytosis are often related to blood clot formation or, paradoxically, bleeding. Common signs include:

• Headaches
• Dizziness or lightheadedness
• Chest pain
• Weakness or numbness on one side of the body
• Visual disturbances
• Unexplained bruising or bleeding

The primary risk associated with thrombocytosis is the formation of blood clots, which can lead to serious conditions such as stroke, heart attack, or deep vein thrombosis. In some cases, extremely high platelet counts can paradoxically cause bleeding problems due to dysfunctional platelets.

Causes of Thrombocytosis

Thrombocytosis can be classified into two main categories:

1. Primary (or Essential) Thrombocytosis: A rare bone marrow disorder where the body produces too many platelets without an apparent cause
2. Secondary (or Reactive) Thrombocytosis: An increase in platelets due to an underlying condition or factor

Common causes of secondary thrombocytosis include:

• Chronic inflammation or infection
• Iron deficiency anemia
• Recent surgery or trauma
• Certain medications
• Some types of cancer

Identifying the underlying cause is crucial for proper management of thrombocytosis. In some cases, treating the primary condition can resolve the high platelet count.

Diagnosis and Interpretation of Platelet Count Test Results

Interpreting platelet count test results requires understanding the normal range and recognizing what constitutes abnormal levels. How do healthcare providers use these results to diagnose platelet disorders?

A normal platelet count typically falls between 150,000 and 450,000 platelets per microliter of blood. Results outside this range may indicate a platelet disorder:

• Below 150,000/μL: Thrombocytopenia
• Above 450,000/μL: Thrombocytosis

However, it’s important to note that a single abnormal result doesn’t necessarily indicate a disorder. Factors such as recent illness, medication use, or even the time of day can affect platelet counts. Therefore, doctors often consider other factors and may order additional tests before making a diagnosis.

Additional Diagnostic Tests

When abnormal platelet counts are detected, healthcare providers may recommend further testing to determine the underlying cause:

• Peripheral blood smear: Examines the size and shape of platelets
• Bone marrow biopsy: Assesses platelet production in the bone marrow
• Genetic tests: Identify inherited platelet disorders
• Antibody tests: Detect immune-mediated platelet destruction

These additional tests help paint a comprehensive picture of platelet function and production, guiding treatment decisions and management strategies.

Treatment Options for Platelet Disorders

The treatment of platelet disorders varies depending on the underlying cause, severity of symptoms, and whether the condition involves low or high platelet counts. What are the common approaches to managing these conditions?

Treating Thrombocytopenia

For low platelet counts, treatment options may include:

• Corticosteroids: To reduce immune system activity in cases of immune thrombocytopenia
• Immunoglobulins: To temporarily boost platelet counts
• Thrombopoietin receptor agonists: Medications that stimulate platelet production
• Platelet transfusions: For severe cases or before surgical procedures
• Splenectomy: Surgical removal of the spleen in certain cases of ITP

In many cases, treating the underlying condition (such as an infection or vitamin deficiency) can resolve thrombocytopenia.

Managing Thrombocytosis

Treatment for high platelet counts often focuses on reducing the risk of blood clots and addressing the underlying cause. Options may include:

• Low-dose aspirin: To reduce platelet stickiness and prevent clot formation
• Hydroxyurea: A medication that can lower platelet production
• Anagrelide: Another drug that can reduce platelet counts
• Plateletpheresis: A procedure to remove excess platelets from the blood in severe cases

For secondary thrombocytosis, treating the underlying condition (such as iron deficiency or chronic inflammation) is often the primary approach.

Lifestyle Modifications and Precautions

In addition to medical treatments, individuals with platelet disorders may need to make certain lifestyle adjustments:

• Avoiding activities with a high risk of injury
• Using soft-bristled toothbrushes and electric razors to minimize bleeding risk
• Limiting or avoiding alcohol consumption
• Staying hydrated to maintain proper blood flow
• Informing healthcare providers about the condition before any medical procedures

These precautions can help manage symptoms and reduce the risk of complications associated with platelet disorders.

Living with Platelet Disorders: Long-Term Outlook and Management

For many individuals diagnosed with platelet disorders, long-term management becomes a part of daily life. But what does this entail, and what can patients expect in terms of prognosis and quality of life?

The long-term outlook for people with platelet disorders varies greatly depending on the specific condition, its severity, and how well it responds to treatment. Many individuals with mild disorders can lead normal, active lives with proper management. However, those with more severe conditions may face ongoing challenges and require regular medical care.

Key Aspects of Long-Term Management

• Regular Monitoring: Frequent blood tests to track platelet counts and adjust treatment as needed
• Medication Management: Adhering to prescribed treatments and being aware of potential side effects
• Lifestyle Adaptations: Making necessary changes to reduce risks associated with the condition
• Dietary Considerations: Some platelet disorders may benefit from specific dietary changes
• Stress Management: Chronic conditions can be stressful, making stress reduction techniques important
• Emergency Preparedness: Knowing when to seek immediate medical attention

It’s crucial for patients to work closely with their healthcare team to develop a comprehensive management plan tailored to their specific needs and lifestyle.

Coping Strategies and Support

Living with a chronic condition like a platelet disorder can be challenging emotionally as well as physically. Patients may benefit from:

• Support Groups: Connecting with others who have similar experiences
• Counseling: Professional help in dealing with the emotional aspects of chronic illness
• Patient Education: Learning as much as possible about the condition to feel more in control
• Family Involvement: Educating family members to create a supportive home environment

With proper management and support, many individuals with platelet disorders can maintain a good quality of life and effectively manage their condition over the long term.

Platelet Count (PLT) Blood Test

Test Quick Guide

The platelet count test is a lab test that measures the number of platelets you have in your blood. Platelets, also known as thrombocytes, are tiny, round cell fragments that circulate in your blood. They are essential for the formation of blood clots, masses of blood the body forms to stop bleeding.

Platelets are one of three main components of the blood along with red and white blood cells.

Platelet count testing can detect when platelet levels are too low or too high. Low platelet levels make it difficult for the body to form blood clots, which can cause excessive bleeding. High platelet levels can cause too much clotting. Blood clots in the blood vessels can become lodged in the lungs, intestines, brain, or heart, and this can result in serious medical conditions.

About the Test

Purpose of the test

The purpose of a platelet count test is to assess your blood’s ability or inability to clot. While platelet counts are often included on multi-test panels such as the complete blood count, this test can also be done on its own.

The platelet count may be conducted by your doctor as part of routine blood testing. Platelet counts are also ordered to:

• Diagnose a platelet disorder
• Assess the risk of bleeding before surgery
• Monitor you during medical treatments such as blood thinners or chemotherapy

The platelet count is used to diagnose disease and help determine the cause of excess bleeding or clotting. Both high and low platelet counts can have associated risks that can range from not causing any noticeable health problems to being very serious and life-threatening.

A platelet count test is also used to monitor if you have been diagnosed with a clotting condition. Regularly conducting a platelet count allows doctors to check the effectiveness of medications that increase or decrease the blood’s ability to form a clot.

What does the test measure?

A platelet count measures the platelets in your sample of blood with the results reported as a number of platelets per microliter. Measuring a platelet count typically involves analyzing a blood sample using automated laboratory technology. In some cases, automated results need to be confirmed using a peripheral blood smear, a method of manually measuring the number of platelets in a blood sample.

When should I get a platelet count test?

Your doctor may recommend you take a platelet count test during a check-up as part of a broader screening panel such as a complete blood count. They might also recommend platelet count testing if you have symptoms associated with abnormal platelet levels. Low or high platelet counts may or may not cause signs and symptoms. It’s important to speak with your doctor any time you notice health changes that concern you.

Symptoms of low platelet levels

Bleeding is the main sign and symptom of a low platelet count. Early signs of a low platelet count can occur in any part of the body and may include (but are not limited to):

• Purple, reddish, or brown bruising, occurring easily and often
• Small red and purple dots on the skin
• Abnormally prolonged bleeding, including from minor cuts
• Bleeding from the nose or mouth
• Atypically heavy vaginal bleeding, especially during menstruation
• Excessive bleeding during dental work, including flossing or surgery
• Blood in the urine or stool, or bleeding from the rectum

Symptoms of high platelet levels

Signs of high platelet levels are primarily related to blot clots and bleeding. They may include:

• Weakness or dizziness
• Unexpected headache
• Chest pain
• Tingling of the hands and feet
• Pain, swelling, warmth, and/or tenderness in one or both of the lower extremities

In some instances, extremely high platelet counts may result in signs and symptoms that mirror low platelet counts. Signs and symptoms of high platelet levels include:

• Bleeding from many sites of the body at once
• Shortness of breath
• Confusion and changes in memory or behavior
• Fever

Monitoring platelet levels

Your health care provider may also order a platelet count test when monitoring other health conditions. If you have been diagnosed with a disease that puts you at risk for high or low platelets, or if you have had abnormal results on past platelet count tests, your doctor may test you for platelet levels periodically. This allows your doctor to monitor your overall health and assess the effectiveness of treatment.

Finding a Platelet Count Test

How can I get a platelet count test?

Typically, a platelet count test is done by a licensed professional in a health care setting using a blood sample. The test can be conducted on its own or as part of a complete blood count test that is done in a doctor’s office, clinic, laboratory, or hospital.

A platelet count test is normally prescribed by a doctor. Talk with your health care provider if you have symptoms that could be related to abnormal platelet levels or if you are interested in a platelet count test.

You can order a platelet test online with a blood draw at a local lab.

Can I take the test at home?

Currently, there are no at-home testing options available for the platelet count. A medical professional conducts platelet counts and they are analyzed by a laboratory from a blood draw sample in a health care setting.

How much does the test cost?

The cost of a platelet count test depends on whether or not you have insurance and if that insurance plan covers the test. Some other factors that affect the price are the setting of the blood draw and the lab to which the sample is sent.

For details on the expected cost for a platelet count that you may be responsible for, check with your doctor or insurance provider about any associated copays or deductibles.

Taking a Platelet Count Test

The platelet count test requires a blood sample ordered by a doctor that is collected in a medical setting by a licensed professional, such as a phlebotomist.

Before the test

No special preparation is required prior to a platelet count test unless specified by your health care provider. They may order the platelet count by itself, as part of the complete blood count, or along with other blood tests.

If you are receiving more than one blood test, your provider may ask you to not eat anything for a certain amount of time prior to your test. Contact your health care provider for detailed instructions if you have questions or concerns about any test preparation.

During the test

A blood sample for a platelet count is taken from a vein in your arm or forearm by a phlebotomist, a health care professional trained in drawing blood. They tie a tourniquet around the upper part of your arm to increase the blood pressure in the vein so it is easier to find.

They will cleanse your skin around the vein with an antiseptic wipe and insert a needle to draw blood from the vein. Next, they attach a vacuum tube to the needle to help pull blood from the vein and, if drawing blood for multiple tests, they may attach several different tubes.

There may be a brief stinging sensation when the needle is initially inserted into your arm. This pain usually does not last long, and the test itself can be completed in under one minute.

After the test

After the procedure is complete, the phlebotomist will apply folded gauze and an adhesive bandage over the site to reduce bleeding, as well as remove the tourniquet and needle.

The main risk associated with blood draws is local bruising at the site of the needle puncture. This bruising may last longer than usual if you are experiencing low platelets. Because low platelet counts reduce the clotting potential of your blood it may be suggested to keep the bandage on for a specified period of time.

The phlebotomist may ask you to stay at the facility for a few minutes so they can monitor you for dizziness before you return to normal activities including walking and driving.

Platelet Count Test Results

Receiving test results

The results from a platelet count can be available in a few minutes or up to a few days after the blood sample arrives at the laboratory, depending on the equipment that is used.

If not available immediately, a copy of your results may be sent to you by mail or through an electronic health portal. It is also possible that your health care provider may call you to discuss the results, retest, or schedule an appointment to review them together.

Interpreting test results

Results are interpreted in comparison with the test reference range, the results range that is considered to be normal. Platelet test results that fall outside of the reference range indicate that platelet levels may be too low or too high.

The reference range for platelet counts gives a wide range of normal results. This reflects the range in platelet levels that allows most people to function without adverse health issues. Specific reference ranges vary from one laboratory to the next, and your results are considered in the context of your overall health risk factors.

The American Board of Internal Medicine lists a typical platelet count reference range as 150,000 to 450,000 per microliter.

Platelet counts tend to be slightly higher in certain populations, including:

• Females
• Younger people when compared with older people
• Non-Hispanic Black individuals when compared with white individuals

Your doctor may consider retesting if you have significant decreases or increases in your platelet numbers from one test to the next even if they are within the normal range as this may indicate a potential problem.

If you have a platelet count test result that is lower than expected, your doctor will consider whether another condition may be causing or contributing to a decrease in platelets. Some causes and risk factors associated with low platelet counts are:

• Certain cancers
• Aplastic anemia
• Autoimmune diseases and conditions
• Certain medications
• Viral or bacterial infections
• Genetic condition
• Heavy alcohol use
• Pregnancy

Other conditions can cause or increase the risk for high platelet counts:

• Rare genetic conditions
• Bone marrow conditions
• Certain cancers
• Iron deficiency or hemolytic anemia
• Inflammatory disease
• Infections such as tuberculosis
• Adverse medication reactions
• Severe blood loss
• Recovery from low blood platelet counts caused by heavy alcohol use or vitamin B12 or folate deficiency
• Physical activity

Depending on the results of your platelet count test, it is possible that your doctor will order follow-up tests to learn more about your overall health. Commonly ordered follow-up tests include:

• Complete blood count: If your platelet count does not match the context of your symptoms and other test results, your doctor may reorder a complete blood count panel to confirm the results prior to more extensive evaluations or interventions.
• Peripheral blood smear: Automated instrumentation is most often used to measure blood counts, including platelet counts. A peripheral blood smear involves manually analyzing the blood sample under a microscope and can be used to confirm an abnormal result on an automated platelet count.
• HIV or HCV test: Low platelet counts are often seen if you have human immunodeficiency virus (HIV) or hepatitis C virus (HCV) infection. Follow-up testing may be used to rule out or confirm the existence of HIV or HCV as the cause of low platelets.

Other tests may be conducted to diagnose the cause of abnormal platelets. Testing depends on the specific conditions that are suspected. If you receive an abnormal platelet count result, your doctor can help you understand what follow-up testing is recommended for you and why.

It may be helpful to ask your doctor the following questions about your platelet count results:

• Was my test result abnormal? If so, was it abnormally high or low?
• What does my platelet count indicate about my health?
• Are there any diagnoses to be made based on my platelet count results?
• Will any follow-up tests be needed?
• Will I be prescribed medication based on my results?

• Platelet Function Tests
  Learn More
• PTT Blood Test (Partial Thromboplastin Time)
  Learn More
• PT/INR Test (Prothrombin Time and International Normalized Ratio)
  Learn More
• Protein C and Protein S
  Learn More
• CBC Blood Test (Complete Blood Count)
  Learn More
• HIV Testing
  Learn More
• Hepatitis C Test
  Learn More
• Blood Smear
  Learn More
• von Willebrand Factor
  Learn More
• D-Dimer Test
  Learn More

Resources

• National Library of Medicine: Platelet Disorders
• National Library of Medicine: Bleeding Disorders

Sources

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What Are Platelets and Why Are They Important?

“Platelets are the cells that circulate within our blood and bind together when they recognize damaged blood vessels,” says Marlene Williams, M.D., director of the Coronary Care Unit at Johns Hopkins Bayview Medical Center. “When you get a cut, for example, the platelets bind to the site of the damaged vessel, thereby causing a blood clot. There’s an evolutionary reason why they’re there. It’s to stop us from bleeding.”

What makes platelets change their shape?

Platelets, the smallest of our blood cells, can only be seen under a microscope. They’re literally shaped like small plates in their non-active form. A blood vessel will send out a signal when it becomes damaged. When platelets receive that signal, they’ll respond by traveling to the area and transforming into their “active” formation. To make contact with the broken blood vessel, platelets grow long tentacles and then resemble a spider or an octopus.

What is a healthy platelet count?

A normal platelet count ranges from 150,000 to 450,000 platelets per microliter of blood. Having more than 450,000 platelets is a condition called thrombocytosis; having less than 150,000 is known as thrombocytopenia. You get your platelet number from a routine blood test called a complete blood count (CBC).

What it means to have too many platelets

The medical term for having too many platelets is thrombocytosis, and there are two types:

• Primary or essential thrombocytosis – Abnormal cells in the bone marrow cause an increase in platelets, but the reason is unknown.
• Secondary thrombocytosis – The same condition as primary thrombocytosis, but may be caused by an ongoing condition or disease such as anemia, cancer, inflammation, or infection.

When there are symptoms, they include spontaneous blood clots in the arms and legs, which if untreated can lead to heart attack and stroke. In severe cases, the patient might have to undergo a procedure called a platelet pheresis. This lowers the platelet count by removing the blood, separating out the platelets, and returning the red blood cells back to the body.

With secondary thrombocytosis, the symptoms are usually related to the associated condition. For example, if you have an infection or anemia, you treat those conditions and the platelet count comes down.

What it means to have too few platelets

When you don’t have enough platelets, it’s called thrombocytopenia. Symptoms include easy bruising, and frequent bleeding from the gums, nose, or GI tract. Your platelet count drops when something is preventing your body from producing platelets. There are a wide range of causes, including:

• Medications
• An inherited condition
• Certain types of cancer, such as leukemia or lymphoma
• Chemotherapy treatment for cancer
• Kidney infection or dysfunction
• Too much alcohol

How platelets relate to cardiovascular disease

If you have too many platelets, it can increase your risk for clotting. But often your cardiovascular risk has more to do with platelet function than platelet number. For example, you could have a healthy number of platelets, but if they’re sticking together too much it can increase your chance of having a heart attack or stroke.

Keeping track of your platelets

Too many platelets, too few platelets, abnormally functioning platelets, and related conditions such as blood clots, strokes, and heart attacks can be inherited. So it’s a good idea to alert your doctor when there’s a family connection.

“Although you may feel fine, your physician might want to keep a close eye on you and investigate whether or not you need medications to reduce the functioning of your platelets,” says Williams. “The most common blood-thinning medication is aspirin, although recent studies have shown that women under 65 who are otherwise healthy do not receive the same benefit from aspirin as men do. There is no concrete answer to that yet.”

Platelets

Platelets are blood cells whose main function is to participate in blood clotting.

Synonyms Russian

Blood plates, Bizzocero plaque.

Synonyms English

Platelet Count, Thrombocyte, Thrombocyte count, PLT.

Units

*10 ⁹ /l (10 in st. 9/l).

What is this analysis used for?

To detect clotting disorders or diseases of the bone marrow.

When is the test ordered?

• Complete blood count, which is required for various reasons.
• In cases of unexplained or prolonged bleeding.
• When diagnosing a disease of the bone marrow or when monitoring its course.

Which biomaterial can be used for research?

Venous or capillary blood.

General information about the study

Platelets, like other blood cells, are formed in the bone marrow. Some stem cells in the bone marrow turn into megakaryocytes, from which platelets are “cleaved off” and released into the blood. They are devoid of a nucleus and are relatively small (2-3 microns in diameter), they are the smallest blood cells.

Damage to the vessel causes the formation of substances that convert platelets into an active form. Platelets flatten and acquire the ability to stick together with each other and with the vessel wall, creating a thrombus, which helps stop bleeding.

The lifespan of platelets is about 10 days, so their constant renewal is required. If there is no balance between the formation of platelets in the bone marrow and destruction, there may be a tendency to increased bleeding or, conversely, to thrombosis.

The analysis counts the number of platelets per unit of blood, either in a liter or in a microliter.

What is research used for?

The need to determine the number of platelets, as well as their functionality, may arise with clotting disorders or diseases of the bone marrow, such as leukemia (and if they are suspected).

When is the test ordered?

Counting the number of platelets, as a rule, is included in the routine complete blood count, which is carried out both on a planned basis and in various diseases and pathological conditions, before surgical interventions.

This test is indicated for patients who suffer from unexplained bruising, excessive menstrual bleeding, bleeding gums, nosebleeds, or who bleed from a small wound for a long time. 99/l

A significant increase in the number of platelets (more than 1 billion per liter (1000 * 10 ⁹ / l) contributes to their more active “gluing” and thrombosis. In adults, the normal number of platelets ranges from 150 to 450 million per liter of blood (150-450 *10 ⁹ /l) If they fall below 20 million per liter (20 *10 ⁹ /l), this can lead to spontaneous bleeding and threaten the life of a person. Reduction of platelets to less than 5 million per liter (5 *10 ⁹ /l) is highly likely to cause death.

Causes of elevated platelets

• Malignant tumors in the bone marrow (myeloproliferative diseases) and other organs.
• Polycythemia vera.
• Iron deficiency anemia.
• Tuberculosis.
• Injuries, acute or chronic infections.
• Removal of the spleen (because old platelets are destroyed in it).
• Inflammatory bowel disease.
• Autoimmune diseases (systemic lupus erythematosus, rheumatoid arthritis).
• Renal failure.
• Severe blood loss.

Causes of low platelets

• Decreased production of platelets in the bone marrow.
• Increases the speed of their destruction or use.
• Immune thrombocytopenic purpura is the most common cause of excessive platelet destruction. In this case, antibodies to their own platelets appear. Antibodies bind to platelets, which causes them to be rapidly destroyed, so that their lifespan is reduced to several times

Gulidova O. V.

Experienced surgeons know that even when using well-established technologies and tactics for managing an operating patient, the doctor is not immune from emergencies. Of particular danger are surgical and postoperative hemostasiological complications, which manifest themselves in the form of bleeding or thrombosis.

The risk of developing postoperative thromboembolism increases with increasing age of patients, types, severity and duration of surgical interventions, the background state of the hemostasis system (the presence of hereditary or acquired thrombophilic conditions, vascular diseases and hemorheological disorders), the presence of diseases that create a particularly high predisposition to thrombosis – varicose veins veins, hyperlipidemia and atherosclerosis, diabetic angiopathy, malignant neoplasms (oncothrombosis), etc.

A special group of risk factors are hereditary and acquired (secondary) thrombophilias, among which forms characterized by polyglobulia (high hematocrit and hemoglobin levels in the blood), hyperthrombocytosis (more than 450-500´10 ⁹ /l), spontaneous hyperaggregation of platelets, anomalies of coagulation factors, especially factors V and II, making them resistant to physiological anticoagulants, deficiency of the latter (antithrombin III, proteins C and S) and components of the fibrinolysis system, antiphospholipid syndrome.

Increase the risk of thrombosis and some medications – taking many hormonal contraceptives and a number of anticancer drugs, in some patients – heparin therapy (the so-called “heparin thrombotic thrombocytopenia”, GTT), etc.

Accounting for all of the listed risk factors separately and together allows for timely targeted prevention of thromboembolism. The groups of people with a very high risk of such thromboembolism, regardless of all other factors, include patients undergoing orthopedic operations on the lower extremities, including arthroplasty, operated on for visceral cancers, patients with any type of thrombophilia and with a history of lower extremity vein thrombosis.

The risk of arterial thromboembolism is especially high in patients with atherosclerosis who have had NCC and strokes in the past, with high blood pressure, paroxysmal or persistent atrial fibrillation, after commissurotomy and implantation of artificial heart valves, as well as with aneurysms of the main arteries. This risk is exacerbated by certain thrombophilias, hyperhomocysteinemia, diabetes, obliterating diseases of the arteries of the lower extremities. With a number of these types of pathology, there is a high risk of developing both arterial and venous thromboembolism. In the prevention of all these thromboses and embolisms, anticoagulants, inhibitors of platelet aggregation, as well as agents that increase endothelial thrombosis resistance and improve blood rheology, play a leading role, and in the treatment of already formed thrombi, thrombolytics in combination with anticoagulants and antiaggregants.

Based on the foregoing, it is clear that the success of the operation depends on how accurately the hemostatic status of the body is established, on the preparedness of the patient for surgical intervention. The effectiveness of the preoperative examination is entirely determined by the joint coordinated work of the attending physician and the doctor of the clinical diagnostic laboratory.

The meaning of a high-quality preoperative coagulogram is seen in the determination of not individual trends – a decrease or increase in fibrinogen, the detection of a hyper- or hypocoagulation shift, which in itself is not sufficiently informative, but the diagnosis based on known algorithms of the most common syndromes in the clinic, the selection of patients for grouping the risk of developing postoperative thromboembolism, monitoring the conduct of antithrombotic, anticoagulant therapy, identifying the risk of bleeding, etc. In other words, the laboratory is faced with the task of finding, with the help of a minimum number of tests, the shortest path to a diagnosis, abandoning the little useful one-type examination of patients with different types of pathology.

And so, the initial preoperative examination of the patient includes a set of tests showing how likely the development of a thrombotic or hemorrhagic complication in the examined patient and what preventive measures or additional studies are needed.

Bleeding risk determination

TEST	NORM	DEVIATION
Blood platelet count	(150 – 370)*10 9 /l	<100*10 9 /l – hemorrhagic manifestations
Bleeding time	5-8 min	extended
APTT (APTT)	25 – 35 from	extended
Prothrombin time	11-15 from	extended
Plasma fibrinogen	2 – 4 g/l	reduced

Thrombosis risk assessment

TEST	NORM	REJECTION
RFMK in plasma by ortho-phenanthroline test	3. 0-4.0 mg%	more than 10 mg%
Antithrombin III activity	80 – 120%	<80% - high risk of thrombosis
Protein C	70 – 130%	<70% - high risk of thrombosis
Factor Va resistance to protein C	NO >0.8	<0.8 - high risk of thrombosis
Presence of lupus anticoagulant (Rapid lupus test)	0.7 – 1.19	1.2 -1.29 doubtful result more than 1.3 positive result

A competent doctor in a diagnostic laboratory is the first assistant to a surgeon. What is not visible to the eye, those processes that have not yet given clinical signs of pathology, have already manifested themselves in laboratory tests. The CDL doctor does not see the patient, but he can very accurately characterize his hemostatic status. Here, the attending physician is required to correctly formulate the task – the purpose of the examination. Be sure to indicate the presence of hemorrhagic (nose, uterine or other bleeding), and / or thrombotic manifestations. Give information about the ongoing treatment that can affect the parameters of hemostasis, their dosages and the timing of the last administration. This information will allow you to make a correct conclusion. If abnormalities are detected in screening tests, a decision is made on preventive preoperative measures or on the need for additional laboratory testing to clarify the cause of coagulation abnormalities. Let us consider in more detail the clinical interpretation of the indicators of the main tests.

Determination of platelet count

In surgical operations complicated by bleeding, disturbances in the system of vascular-platelet hemostasis in most cases are not caused by a violation of aggregation or other functional properties of platelets, but by the presence of thrombocytopenia of varying degrees (see Table 1). Normally, these cells live in the body for 7-10 days. A decrease in the number of platelets can occur due to many processes.

Reduced platelet production cause adenovirus infections, some antibiotics, liver diseases, ionizing radiation, megaloblastic anemia, tumor diseases, hereditary pathologies of platelet formation (Fanconi, Wiskott-Aldrich, Bernard-Soulier syndromes, May-Heglin anomaly). Increased destruction of platelets occurs in autoimmune diseases, prosthetic heart valves, extracorporeal circulation. The number of platelets can decrease sharply when they are intensive consumption with DIC, thrombotic thrombocytopenic purpura. It should be borne in mind that in women during menstruation, the number of platelets can decrease up to 25-50%.

Activated partial thromboplastin time (APTT)

This is the most valuable of the general tests, revealing exclusively plasma defects in the intrinsic factor X activation system. Prolongation of APTT indicates the predominance of hypocoagulation. For all cases of detecting an extended APTT, an additional examination is necessary to establish the cause and choose methods for correcting and preventing possible bleeding.

Prolongation of APTT with normal prothrombin and thrombin time is observed only with deficiency or inhibition of factors VIII, IX, XI, XII, as well as prekallikrein and kininogen.

Corrective tests are performed in the laboratory for differential diagnosis. When confirming the deficiency of any factor, it is necessary to evaluate its activity in%. To perform operations, the minimum hemostatic level of factors VIII, IX, XI is 25%, with a lower activity of one of the factors, the risk of postoperative bleeding is extremely high.

In the absence of a positive result in corrective tests, an examination for the detection of lupus anticoagulant is necessary.

Coagulation retardation (both APTT and prothrombin test ) is observed with a deficiency of X, V, II factors, and under the influence of indirect anticoagulants.

Prolongation of APTT, prothrombin and thrombin time is observed with deep hypofibrinogenemia, treatment with fibrinolysis activators and with treatment with heparin. It is known that patients can be with increased and decreased sensitivity to heparin. To resolve the issue of tolerance to heparin, the APTT is re-determined 1 hour before the next injection. If the APTT is more than 2 times higher than normal, hypersensitivity is noted.

Determination of soluble fibrin (RF or RFMK)

The end result of blood coagulation is known to be thrombin-induced transformation of fibrinogen into fibrin. In a number of pathologies characterized by intravascular coagulation (DIC, thrombosis, thrombophilia), an increased amount of intermediate products of fibrinogen transformation into fibrin circulates in the blood – fibrin monomer and its oligomers, referred to as soluble fibrin (RF) or soluble fibrin-monomeric complexes – RFMK. Determination of an increased amount of soluble fibrin in plasma is of great diagnostic value, since this protein is a marker of thrombinemia and intravascular coagulation.

Paracoagulation tests, ethanol and protamine sulfate, have traditionally been used to detect MFMC in the clinic. However, they are not informative enough, give false positive results in hyperfibrinogenemia and false negative in hypofibrinogenemia, and only qualitatively reflect the process of transformation of fibrinogen into fibrin. Many researchers consider these tests obsolete and out of use. In recent years, a paracoagulation ortho-phenanthroline test (PT) has been developed and widely used, reflecting the content of soluble fibrin in plasma and the presence of thrombinemia. Approbation of this test in many laboratories has shown that FT allows quite reliably not only qualitatively, but also quantitatively determine the content of soluble fibrin in plasma, including in the conditions of express diagnostics. This opened up prospects for a more accurate assessment of the severity of intravascular coagulation and dynamic monitoring of the effectiveness and sufficiency of therapy for DIC and thrombosis.

Prothrombin test

Synthesis of prothrombin complex factors occurs in the liver with the participation of vitamin K. Indirect anticoagulants inhibit the final stage of synthesis in hepatocytes (carboxylation) of vitamin K-dependent coagulation factors. The efficacy and safety of AEDs are monitored by the indications of a standardized prothrombin test, which should be performed taking into account the sensitivity index of the thromboplastin used in the test (ISI) to depression of prothrombin complex factors. Currently, the Russian Federation produces several thromboplastins standardized according to ISI, which is indicated on the packages of this reagent. For different thromboplastins, this index varies from 1.1 to 1.5, which is taken into account when calculating the international normalized ratio (INR), which guides when choosing the right doses of AED. INR is calculated using the following formula:

INR = (PV of patient plasma / PV of control normal plasma) ^ISI

. Currently, a number of countries produce coagulometers that immediately give the result of a prothrombin test for INR. This greatly simplifies the control of dosages of AEDs, allows you to more often evaluate the effect of these drugs, avoiding their overdose.

Antithrombin III activity

It should be taken into account that the anticoagulant and antithrombotic effects of heparins are realized by their complex connection with plasma antithrombin III (AT III). Therefore, with a deep deficiency of AT III, the effect of these drugs is sharply reduced, which is observed in thrombophilia due to AT III deficiency and in some consumption coagulopathy. This decrease in the effectiveness of heparins can be temporarily reversed by transfusions of fresh frozen plasma that contains AT III, or by intravenous administration of AT III concentrate.

To conduct a full-fledged preoperative coagulological examination in each health facility, there is no need to purchase extra expensive equipment and reagents.