Prothrombin time test clotting assay

The prothrombin time (PT), as proposed by Quick, is the most commonly performed coagulation function test. It is used to monitor oral anticoagulant therapy and also as a preoperative screening test to warn of possible bleeding risk in patients with a personal or family history of bleeding (Table 36-2). Measured clotting times are extremely dependent on the animal and tissue source and the quality of the thromboplastin used. Variability can be expected because of the assay s dependence on the number of tissue factor molecules and the quantity of... 

There are many other coagulation tests described in the literature which investigators have used to evaluate the lipid materials. These include the whole blood clotting time in glass or silicone-treated tubes, the thrombin generation test, and the prothrombin consumption test using clotted blood or platelet-free native plasma. In general they are modifications or variations of the basic principles involved in the assays mentioned above. 

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