What is this test?
The Prothrombin time (PT) is a test that helps evaluate your body’s ability to appropriately form blood clots.
 
Sample required
Blood.
 
Patient preparation
No specific patient preparation protocol is required. Inform your doctor if you are on any medications or have any underlying medical conditions or allergies before undergoing this test.
 
Turn-around time (How long does it take?)
5 Hours.
 
Basis of the Test
A PT measures the number of seconds it takes for a clot to form in your sample of blood after substances (reagents) are added. The PT is often performed along with a partial thromboplastin time (PTT) and together they assess the amount and function of proteins called coagulation factors that are an important part of proper blood clot formation. For people taking warfarin, most laboratories report PT results that have been adjusted to the INR. A prolonged PT means that the blood is taking too long to form a clot, this may be caused by conditions such as liver disease, vitamin K deficiency, or a coagulation factor deficiency (e.g., factor VII deficiency).