Determination of clottable fibrinogen in human plasma

An improved rapid method and kinetic study

Abstract

Clottable fibrinogen in human plasma was determined by messuring spectrophotometrically the increase in turbidity with time due to the fibrinogen-fibrin conversion with thrombin. From the maximal absorbance, A_max, at 450nm obtained 2min or less after the addition of thrombin to plasma, the fibrinogen concentration was estimated in plasma of normal subjects and patients. Analysis of the rate of the absorbance increase yielded the K_m value, 1.6×10^-5M, which closely agrees with K_m=1.2×10^-5M obtained by analysis of the fibrinopeptides released from fibrinogen.