The history of phenotypic testing in thrombosis and hemostasis.

This article takes the reader through a journey of the history of the phenotypic tests for hemostasis and thrombosis starting from the most simple (which were based on the visual inspection and recording of the time needed for native whole blood to clot) to the more complex ones based on the addition to plasma of exogenous substances, use of sophisticated coagulometers or synthetic substrates, and use of computer software to record coagulation times or visualize coagulation tracings and thrombin generation curves. One can see how the simple tests evolved over the years and how such old and time-honored tests as thrombin generation and thromboelastography, devised more than 50 years ago and neglected for many years, are now gaining momentum thanks to the progress made by the technology combined with a better understanding of the coagulation mechanisms. This progress notwithstanding, it should be realized that current tests are still somewhat far from being adequate to investigate hemostasis and thrombosis. The challenge in the future will be to devise newer tests mimicking more closely what occurs in vivo.