Prothrombin time test
Definition
Prothrombin is a clotting factor produced by your liver that helps your blood to clot. A prothrombin time test, also called a pro time test, measures the time it takes for the liquid portion of your blood (plasma) to clot. The prothrombin time test measures the time it takes prothrombin to turn into thrombin, a step in the clotting process.
Your doctor may use a prothrombin time test to monitor the effectiveness of blood-thinning medications. Such medications extend clotting time in order to decrease the chance of forming a blood clot without increasing the risk of bleeding. An increased prothrombin time test result could also indicate a problem with your liver and its ability to produce clotting factors.
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