Quantitation of factor XIII by SDS polyacrylamide gel electrophoresis.

An electrophoretic method for the determination of f.XIII, based on the capability of f.XIIIa to cross-link fibrin clots (5) was studied, and the great sensitivity of the method confirmed. Thus, with suitable technical conditions, f.XIII activities less than 0.1% of that in normal human plasma could be detected. The results obtained in plasma from various patients and in f.XIII concentrates (cryoprecipitates) corresponded well with those obtained with the dansylcadaverine method (3) and with the urea solubility test, with two exceptions: In a patient with severe congenital f.XIII deficiency, only the present method was sensitive enough to detect any f.XIII-activity (about 0.1%), and in a patient with an inhibitor against f.XIIIa, the dansylcadaverine method failed to detect this. The present method is too laborious for routine screening, but is recommended as an alternative references method. It may prove especially suitable to detect minute amounts of f.XIII.