Drs Federman and Kirsner provide an excellent review of the hypercoagulable disorders.1 Clearly, the number of these disorders are increasing by the year; however, our knowledge of what to do with the results is not quite keeping up.
In their article, they make a statement to the effect that the levels of protein C, protein S, and anti–thrombin III should not be measured at the time of an acute episode of thrombosis because the levels are decreased during an acute event. They recommend measuring levels of protein C and protein S several months down the road, which would necessitate discontinuing warfarin therapy, usually for a period of 14 days, and potentially covering with daily injections of low-molecular-weight heparin.
Kovacs MJ. Timing of Hypercoagulable Screens. Arch Intern Med. 2002;162(5):613-614. doi: