Platelet Count Test
Why am I having this test?
Platelets are specialized cells that help the blood clot. When you get a tissue injury like a cut, platelets gather at the site of the injury to stop the bleeding. You may have a platelet count test:
- If you have symptoms that may be related to excess bleeding or delayed blood clotting, such as:
- To help monitor treatment for:
What is being tested?
This test measures how many platelets you have within a specific amount (volume) of blood.
What kind of sample is taken?
A blood sample is required for this test. It is usually collected by inserting a needle into a blood vessel or by sticking a finger with a small needle.
Tell a health care provider about:
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Any allergies you have.
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All medicines you are taking, including vitamins, herbs, eye drops, creams, and over-the-counter medicines.
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Any blood disorders you have.
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Any surgeries you have had.
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Any medical conditions you have.
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Whether you are pregnant or may be pregnant.
How are the results reported?
Your test results will be reported as a value that indicates how many platelets are in the blood volume. This will be given as platelets per cubic millimeter (mm3) of blood.
Your health care provider will compare your results to normal ranges that were established after testing a large group of people (
reference ranges). Reference ranges may vary among labs and hospitals. For this test, common reference ranges are:
Adult or elderly: 150,000–400,000/mm3.
Child: 150,000–400,000/mm3.
Infant: 200,000–475,000/mm3.
Premature infant: 100,000–300,000/mm3.
Newborn: 150,000–300,000/mm3.
What do the results mean?
A result that is within your reference range is considered normal, meaning that you have a normal amount of platelets in your blood.
A result that is higher than your reference range means that you have too many platelets in your blood. This may mean that you have:
Certain types of cancer, such as leukemia or lymphoma.
A condition in which the bone marrow produces excess amounts of all cell types, including platelets (polycythemia vera).
A condition that can occur after surgery to remove the spleen (post-splenectomy syndrome).
Rheumatoid arthritis.
Anemia due to lack of iron (iron-deficiency anemia).
A result that is lower than your reference range means that you have too few platelets in your blood. This may mean that you have:
A condition in which the spleen breaks down platelets faster than normal (hypersplenism).
A hemorrhage somewhere in your body.
Low platelet count due to your body's disease-fighting system attacking your platelets (immune thrombocytopenia).
Cancer. Chemotherapy treatments for cancers such as leukemia can also cause low platelet count.
A rare, serious form of thrombocytopenia that causes blood clots (thrombotic thrombocytopenia).
HELLP syndrome, a disorder of pregnancy that causes high blood pressure and other serious problems.
Certain disorders that are passed from parent to child (inherited) that cause a low platelet count.
A condition in which the proteins that control blood clotting are overactive, causing abnormal clotting processes to occur (disseminated intravascular coagulation, DIC).
A disease that causes long-term inflammation and pain in many parts of the body (systemic lupus erythematosus, SLE).
Certain types of anemia, such as pernicious anemia or hemolytic anemia.
Infection.
Talk with your health care provider about what your results mean.
Questions to ask your health care provider
Ask your health care provider, or the department that is doing the test:
When will my results be ready?
How will I get my results?
What are my treatment options?
What other tests do I need?
What are my next steps?
Summary
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Platelets are specialized cells that help the blood clot. When you get a tissue injury like a cut, platelets gather at the site of the injury to stop the bleeding.
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This test measures how many platelets you have within a specific amount (volume) of blood.
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Talk with your health care provider about what your results mean.
This information is not intended to replace advice given to you by your health care provider. Make sure you discuss any questions you have with your health care provider.