A questionnaire indicating the presence of a history or physical findings consistent with liver desease or bleeding disorders was completed by house officers on 301 admissions to a Veterans Administration medical service. Each patient had prothrombin time determined on admission. Only two of 107 patients for whom the prothrombin time was measured as a screening test had an abnormal results and ...

In 1943 Quick (1) reported on the multiple nature of plasma prothrombin. On the basis of his data, which have been repeatedly confirmed (24), he concluded that prothrombin consists of two essential factors combined with calcium. The two components, "prothrombin A" and "prothrombin B," had different properties. The former was labile in oxalated or citrated plasma stored at refrigerator temperatu...