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Platelet count
Thrombocyte 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.
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.
Normal Results
The normal number of platelets in the blood is 150,000 to 400,000 platelets per microliter (mcL) or 150 to 400 x10^9/L.
Normal value ranges may vary slightly. Some lab 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. If you do not have enough platelets, you may bleed too much.
If your platelet count is below 50,000, your risk of bleeding is much higher. Even every day activities can cause bleeding. If your platelets are low, you need to know how to prevent bleeding and what to do if you are bleeding.
A lower-than-normal platelet count is called thrombocytopenia . Low platelet count can be divided into 3 main causes:
Thrombocytopenia
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. ...
- 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
3 of the more common causes of this problem are:
-
Cancer treatments, such
chemotherapy
or
radiation
Chemotherapy
The term chemotherapy is used to describe cancer-killing drugs. Chemotherapy may be used to:Cure the cancerShrink the cancerPrevent the cancer from ...
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Radiation therapy uses high-powered x-rays, particles, or radioactive seeds to kill cancer cells.
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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...
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Autoimmune disorders
, in which the immune system mistakenly attacks and destroys healthy body tissue, such as platelets
Autoimmune disorders
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...
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HIGH PLATELET COUNT
A high platelet count is 400,000 or above
A higher-than-normal number of platelets is called thrombocytosis. It means your body is making too many platelets. Causes may include:
-
A type of anemia in which red blood cells in the blood are destroyed earlier than normal (
hemolytic anemia
)
Hemolytic anemia
Anemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues. Normally, red ...
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Anemia due to low iron
Anemia due to low iron
Anemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues. There are man...
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- Cancer
- Certain medicines
-
Bone marrow disease called
polycythemia vera
Polycythemia vera
Polycythemia vera is a bone marrow disease that leads to an abnormal increase in the number of blood cells. The red blood cells are mostly affected....
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Bone marrow making too many platelets without a known cause (
primary thrombocythemia
)
Primary thrombocythemia
Primary thrombocythemia is a condition in which the bone marrow produces too many platelets. Platelets are a part of the blood that aids in blood cl...
Read Article Now Book Mark Article - Recent spleen removal
Some people with high platelet counts may be at risk of forming blood clots . Blood clots can lead to serious medical problems
Blood clots
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...
Risks
Veins and arteries vary in size so it may be harder to take a blood sample from one person than another.
Other slight risks from having blood drawn may include:
- Excessive bleeding
- Fainting or feeling light-headed
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
References
Cantor AB. Thrombocytopoiesis. In: Hoffman R, Benz EJ Jr, Silberstein LE, Heslop HE, Weitz JI, Anastasi J, eds. Hematology: Basic Principles and Practice . 6th ed. Philadelphia, PA: Elsevier Saunders; 2012:chap 26.
Miller JL, Rao AK. Blood platelets and von Willebrand disease. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods . 22nd ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 40.
Review Date: 1/27/2015
Reviewed By: Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.
