Venography in deep venous thrombosis: postoperative screening of patients in prophylaxis studies

Venography is the key diagnostic method of screening for deep venous thrombosis in clinical prophylaxis studies. Although the venographic technique is standardized the outcome is subject to variation for several reasons. The different methodological pitfalls are presented as well as their consequences for the final results of prophylaxis studies, and it is discussed how variations can be minimized.