Prothrombin Time in Dicoumarol Therapy.

In the course of controlling dicoumarol therapy given (a) as a postoperative routine to prevent thrombosis (fifty-five cases) and (b) therapeutically in cases of established venous thrombosis (nine cases), certain peculiarities have been observed in the behaviour of the prothrombin time, particularly in relation to dicoumarol haemorrhage. Two sources of thromboplastin have been used, Russell viper venom and human brain. Data are presented which suggest that the brain extract is to be preferred to venom, for estimations of prothrombin levels are then more in accord with clinical observation. Technical Methods