Photoelectric determination of plasma clotting times.

A photoelectric clot timer is described. The apparatus allows a large analytic capacity, with good precision and correlation to manual methods, and can be used with capillary blood. Prothrombin analysis according to the method of Quick and Owren, the Thrombotest method, and determinations of partial thromboplastin time are applicable to the apparatus. The semiautomated procedure is extremely simple, and the results are independent of the technicians performing the test.