Platelet Function Assay via Platelet Aggregometry (with or without Antigen Binding)

What Does This Test Measure?

Platelet aggregometry evaluates platelet function by observing how platelets stick and clump together in response to specific chemical triggers (like adenosine diphosphate, ADP, or collagen). Some tests may also include antibodies or other factors to assess specific interactions. The result helps determine whether platelets are functioning normally or if they’re impaired, which could affect bleeding tendencies or response to medications.

Why Might You Need This Test?

A platelet function test may be ordered if you have unexplained bruising, bleeding, or nosebleeds despite normal platelet counts. It’s also used before surgeries, to monitor medications like antiplatelet drugs, or to check for conditions like von Willebrand disease or aspirin resistance.

What Does the Result Mean?

Results typically show how strongly platelets aggregate under test conditions. Abnormally low or high aggregation may indicate dysfunction, which could mean increased bleeding risk or poor response to treatment. Your doctor will interpret results in the context of your symptoms and other test results.

How Is the Test Done?

Blood is drawn from a vein, usually in the arm. A small sample is tested immediately in a lab to measure platelet clumping. Some tests may use a special device that mimics blood flow or exposure to triggers like collagen or ADP. The process is quick and generally painless.