Sensitized Clotting Time

This laboratory has been engaged for several years in the development of a simple bedside test of the clotting mechanism, which would indicate an imbalance between the coagulant and anticoagulant factors in the blood. Such a state conceivably might exist after operative trauma, in the presence of manifest thrombosis, after hemorrhage, or as a result of anticoagulant therapy. The first of these studies pertained to a heparin tolerance in vivo, testing the individual's capillary clotting time before and after the intravenous administration of 10 mg. of heparin sodium.¹Later this study was extended to a series of normal controls and compared with patient material.²The test dose, however, was not administered according to body weight,³and, as pointed out by Jaques and Ricker,⁴there is a marked difference between the response to heparin in vivo and in vitro, since in the former the ability of the