The thrombin clotting time. Evaluation of Thromboquik, a commercial thrombin reagent, and observations on sensitivity and on centrifugation.

The thrombin clotting time (TCT) is an important screening test of coagulation, but thrombin can be a troublesome reagent to use, and in general the TCT has not been well standardized, even with respect to the ideal normal range. Thromboquik is a thrombin reagent that is convenient in its day-to-day use and that exhibits prolonged stability after reconstitution. As an extension of an evaluation of this commercial thrombin reagent, the authors have made several observations about the TCT itself. In a comparison between multiple pairs of TCT reagents, the relative extent of departure of clotting times from normal, for any given abnormal plasma sample, was not predictably related to the mean normal clotting times of the two reagents. The authors also concluded that centrifugation of blood at 1,500 X g is inadequate to prepare plasma for the TCT.