Thrombin Generation in Normal Subjects and Cardiac Patients.

• A reliable and sensitive test for both hypoand hypercoagulability would be very desirable for clinical and research purposes. Rapid detection of hypercoagulability would be of value in conditions such as spontaneous clotting fluctuations which occur during stress in patients with congenital or acquired valvular heart diseases < and with previous myocardial infarction. It is difficult to find a test with equal sensitivity for both hypoand hypercoagulability. Thrombelastography, the thromboplastin generation test, and earlier thrombin generation tests do not fulfill these requirements completely. The thrombelastograph undoubtedly can detect marked hypercoagulability ~' but it is less suited for recording finer deviations from the normal; it is also a rather expensive device. The thromboplastin generation test has been used in the past to detect hypercoagulability. It is inferior to thrombin generation although recently a modification designed for hypercoagulability has been described. The thrombin generation test was originally devised for studies on hemophilia."' The test was subsequently used to study clotting abnormalities in cirrhosis of the liver and other diseases,' iron loading deficiencies, and Hageman factor deficiency. We have used it in the method described below to study the neutralizing effect of the human procoagulant from urine on circulating anticoagulants.1T It was instrumental in the discovery of spontaneous clotting fluctuations in certain patients including those subjected to moderate treadmill stress.--