Venous thrombosis and the "Wessler test".

The Wessler test in animals has been used extensively for over 40 years as a laboratory measure of in vivo hypercoagulability. The test, in which induced hypercoagulability is combined with local venous stasis, has contributed significantly to our understanding of the pathogenesis of venous thrombosis and pulmonary embolism. In addition, the Wessler test has proved invaluable for assessing the thrombogenicity of various blood products, as well as for assaying the effectiveness of heparin and heparin fractions.