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Platelet Count


Also known as: Thrombocyte count; PLT
Formal name: Platelet Count
Related tests: CBC; Platelet aggregation

The Test Sample

What is being tested?

Platelets (thrombocytes) are tiny fragments of cells called megakaryocytes that are made in the bone marrow. These fragments (about 2-3 microns in diameter) are released from the bone marrow to circulate in the blood. They are the first components to be activated when there has been an injury to a blood vessel or tissue. Because they are very "sticky," they begin the formation of a blood clot. The platelet count is a test that determines the number of platelets in your blood.

How is the sample collected for testing?

A blood sample is drawn though a needle placed in a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.