CALIBRATION OF CLOT-BASED, COAGULATION-FACTOR ASSAYS USING A FIRST-ORDER EXPONENTIAL EQUATION AND THE METHOD OF NONLINEAR LEAST-SQUARES

A nonlinear mathematical model has been developed which relates the ti me to calcium-initiated formation of a detectable clot in citrated, fa ctor-deficient plasma to the clotting activity of the factor deficient in the plasma. The data of clot-based factor assays fit well the expo nential expression of this scheme, which can be used conveniently in t he clinical laboratory to calibrate the clotting activity of individua l coagulation factors in samples of citrated plasma. Aside from its cl inical utility, the model may prompt the formulation of testable hypot heses not otherwise prompted by the existing, empiric approach to the quantitation of coagulation factor activity.