Comparison of the Thrombotest with the Modified Quick Test

Abstract

With the technical assistance of Paul J. Lasser COUMARIN and indanedione derivatives are widely used anticoagulants. These compounds induce hypoprothrombinemia by depressing the synthesis of factor II (prothrombin), factor VII (proconvertin), factor IX (plasma thromboplastin component, Christmas factor), and factor X (Stuart-Prower factor), and this hypoprothrombinemia is neutralized most effectivelv by phytonadione (vitamin K1). The laboratory control of their dosage has depended primarily upon the Quick one-stage prothrombin time or some modification of this test. This simple test has survived competitive trials with other similar laboratory tests because it is accurate and dependable in the hands of technicians of average laboratory skill. Rodman anid his associates1 emphasized that the most serious faults found with the Quick test can be ascribed to the fluctuations that follow the use of the several varieties of dilution curves and types of thromboplastin preparations available, anid that these criticisms could be eliminated easily if there were a general adherence to a consistent standard of technic and materials. The thrombotest of Owren, another type of one-stage test, has been reported to mirror the drug-induced depressions of the prothrombin complex with greater accuracy and sensitivity. It has been said, as well, to be sensitive to factor IX depressions, which cannot be detected by the Quick test.2 A further advan-