Methods for determination of activities of coagulation factors

An in vitro method of measuring an activity of a coagulation factor of the intrinsic or extrinsic pathway, wherein said coagulation factor comprises any of factor II, factor V, factor VII, factor VIII, factor IX, factor X, factor XI and factor XII, said method comprising: (a) contacting a sample of capillary blood from a test subject comprising whole blood depleted plasma of said coagulation factor, a source of ionic citrate, a source of calcium ion , phospholipid, and one or more of an activator of the contact phase of coagulation and tissue factor; (B) determine the time required for blood coagulation of said sample capillary blood; and (c) correlating said time with the activity of the clotting factor.