A micromethod for clotting tests and coagulation factor assays

A simple microtechnique for carrying out partial thromboplastin time with kaolin tests with 2 microliter or less of test plasma is described. For single stage factor assays, less than 1 microliter of test solution may be used. Reagents and test plasma are loaded in sequence into a 10 microliter, long needle syringe and introduced into a micro test-tube immobilized in a water bath. The end-point is taken as a positive clearing of kaolin turbidity from the mixture while stirring. Correlation with normal techniques has been excellent.