Platelet countThrombocyte count
A platelet count is a lab test to measure how many platelets you have in your blood. Platelets are parts of the blood that help the blood clot. They are smaller than red or white blood cells.
How the Test is Performed
Blood sample is needed
Venipuncture is the collection of blood from a vein. It is most often done for laboratory testing.Read Article Now Book Mark Article
How to Prepare for the Test
Most of the time you do not need to take special steps before this test.
How the Test will Feel
When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or slight bruising. This soon goes away.
Why the Test is Performed
The number of platelets in your blood can be affected by many diseases. Platelets may be counted to monitor or diagnose diseases, or to look for the cause of too much bleeding or clotting.
The normal number of platelets in the blood is 150,000 to 400,000 platelets per microliter (mcL) or 150 to 400 × 109/L.
Normal value ranges may vary slightly. Some labs use different measurements or may test different specimens. Talk to your doctor about your test results.
What Abnormal Results Mean
LOW PLATELET COUNT
A low platelet count is below 150,000 (150 × 109/L). If your platelet count is below 50,000 (50 × 109/L), your risk for bleeding is higher. Even every day activities can cause bleeding.
A lower-than-normal platelet count is called thrombocytopenia. Low platelet count can be divided into 3 main causes:
Thrombocytopenia is any disorder in which there is an abnormally low amount of platelets. Platelets are parts of the blood that help blood to clot. ...Read Article Now Book Mark Article
- Not enough platelets are being made in the bone marrow
- Platelets are being destroyed in the bloodstream
- Platelets are being destroyed in the spleen or liver
Three of the more common causes of this problem are:
- Cancer treatments, such as chemotherapy or radiation
The term chemotherapy is used to describe cancer-killing drugs. Chemotherapy may be used to:Cure the cancerShrink the cancerPrevent the cancer from ...Read Article Now Book Mark Article
Radiation therapy uses high-powered radiation (such as x-rays or gamma rays), particles, or radioactive seeds to kill cancer cells.Read Article Now Book Mark Article
- Drugs and medicines
Drugs and medicines
Thrombocytopenia is any disorder in which there are not enough platelets. Platelets are cells in the blood that help the blood clot. A low platelet...Read Article Now Book Mark Article
- Autoimmune disorders, in which the immune system mistakenly attacks and destroys healthy body tissue, such as platelets
An autoimmune disorder occurs when the body's immune system attacks and destroys healthy body tissue by mistake. There are more than 80 types of aut...Read Article Now Book Mark Article
If your platelets are low, talk to your health care provider about how to prevent bleeding and what to do if you are bleeding.
HIGH PLATELET COUNT
A high platelet count is 400,000 (400 × 109/L) or above.
A higher-than-normal number of platelets is called thrombocytosis. It means your body is making too many platelets. Causes may include:
- Iron deficiency
- After certain infections, major surgery or trauma
- Certain medicines
- Bone marrow disease called myeloproliferative neoplasm (which includes polycythemia vera)
Polycythemia vera (PV) is a bone marrow disease that leads to an abnormal increase in the number of blood cells. The red blood cells are mostly affe...Read Article Now Book Mark Article
- Spleen removal
Some people with high platelet counts may be at risk for forming blood clots or even bleeding too much. Blood clots can lead to serious medical problems.
Blood clots are clumps that occur when blood hardens from a liquid to a solid. A blood clot that forms inside one of your veins or arteries is calle...Read Article Now Book Mark Article
There is 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. Obtaining a blood sample 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
- Multiple punctures to locate veins
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
Cantor AB. Thrombocytopoiesis. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 7th ed. Philadelphia, PA: Elsevier; 2018:chap 28.
Chernecky CC, Berger BJ. Platelet (thrombocyte) count - blood. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures. 6th ed. St Louis, MO: Elsevier Saunders; 2013:886-887.
Schafer AI. Approach to the patient with bleeding and thrombosis. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 162.
Review Date: 1/19/2021
Reviewed By: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.