Platelet Function Test

Overview

A platelet function test measures the rate at which your blood clots. Doctors treating cardiovascular patients often order a platelet function test to see if antiplatelet medications prescribed to prevent blood clots are working at their intended level. Platelet function tests can also help identify the cause of excessive bleeding or to see if bleeding is a risk during surgery.

Blood clotting is your body’s natural response to healing from an injury. Your blood begins to clot because of platelets, cell fragments in the blood that clump together to prevent bleeding. Platelets cause clotting at injury sites, but they can sometimes also clump at the site of deposits of plaque, a fatty substance that builds up in your arteries and can contribute to a heart attack, stroke, or other problems. For this reason, cardiovascular patients are prescribed antiplatelet medications that reduce the ability of platelets to clump together.

In the lab, a technician follows a procedure to fill small sample chambers with blood. The clotting of platelets as it would occur in your body is simulated in the sample chambers and measured as a function of timeThe resulting information allows your doctor to estimate the extent to which antiplatelet medications work.