If you have trouble with excessive bleeding your doctor may order a platelet test to be run on you. This will tell him how long it takes for your blood to clot. Here is how it is performed.
- A tube of blood is drawn from a vein in your arm
- Half of this blood is put into a tube
- It is then vacuumed to draw it through a very thin glass tube that is coated with collagen and epinephrine
- This coating activates the platelets and makes then adhere and aggregation
- The time it takes for a clot to form and stop any other blood from getting through is called the closer time.
- If the time is normal then you have no platelet dysfunction
- The collagen/ADP test is run to confirm an abnormal collagen/EPI test
- If the ADP test is normal and the EPI is abnormal then it may be due to having taken an aspirin.