Thrombinogen

Better known today as prothrombin, a coagulation (clotting) factor needed for the normal clotting of blood.

There is a cascade of biochemical events that leads to the formation of the final clot.

In this cascade, prothrombin is a precursor to thrombin.

Because prothrombin comes before thrombin, it is called prothrombin.

The prothrombin time is a clotting test.

A test done to test the integrity of part of the clotting scheme.

Familiarly called the 'pro time,' the test is the time needed for clot formation after a substance called thromboplastin (+ calcium) has been added to plasma.