PT-Prothrombin Time
A test used for evaluation of the extrinsic and common coagulation pathways and for monitoring oral anticoagulant therapy. The PT is the time in seconds required for a fibrin clot to form after thromboplastin and an optimal amount of calcium chloride have been added to the sample (citrated platelet poor plasma).
Manner for reporting the Prothrombin Time. The PT Ratio is the PT of a test plasma (numerator) divided by the geometric mean (denominator) of the reference interval.