New electromechanical method for the assay of heparin in vitro

A rapid, simple, and accurate in vitro assay for heparin employing a diatomaceous silicate modified plasma and a precision coagulation timer is reported. The method reveals standard deviations of ± 2.5sec. from the average clotting times with a coefficient of variation of about 2 per cent. Sodium heparin U.S.P., heparin reference standard lot H, and the second international standard for heparin have been successfully assayed by this method. The assays have also revealed the stability of sodium heparin to autoclaving and high energy electron irradiation.