The prothrombin consumption test, which originally was carried out on serum one hour after coagulation, is modified. Blood is distributed to several test tubes, and after fixed time intervals, the tubes are centrifuged. The prothrombin of the serum of each tube is determined immediately and every fifteen minutes within the limits of one hour from the time the blood is taken.
The prothrombin consumption shows considerable variations in normal individuals. In hemophilia and in thrombocytopenia it is very incomplete. In hypoprothrombinemia the prothrombin may be very complete as in congenital hypoprothrombinemia of the Component A deficiency type, or surprisingly incomplete as in dicumarol hypoprothrombinemia. The possible significance of prothrombin consumption in relation to hemostatasis is discussed.