Prothrombin Test (PT), also known as Pro Time Test, is a blood test that measures how long it takes for blood to clot. Often used for identifying bleeding problems, it is also used to check if medicines (mostly Warfarin) that prevent blood clots are effectively working. Prothrombin Test is important as it checks for the presence of five different blood clotting factors (factors I, II, V, VII, and X). Prothrombin or Factor II is made by the liver aided by a sufficient amount of Vitamin K. A doctor suggests a PT Test for symptoms such as excessive bleeding, bleeding gums, blood in urine or stool, heavy periods for women, bone marrow and liver problems, Vitamin K deficiency and leukemia.