Three-Hour Prothrombin Consumption Test in Siliconized Glass: Diagnostic Value in First-Phase coagulation Defects

Abstract

The consumption of clotting factor-II (prothrombin) was sequentially studied in blood from 100 normal subjects, allowed to clot in silicone-coated glassware. Not less than 3 hr. after the blood was collected, the residual factor-H determinations were reproducible, and the values were consistently below 30% in 99% of normal subjects. Patients with clotting abnormalities were studied. When compared with the values obtained with the conventional 1-hr. consumption test done in ordinary glass, the 3-hr. test was more sensitive in disclosing deficiencies of certain clotting factors that were not otherwise demonstrable except by specific assays or by thromboplastin generation studies. This test which is technically simple can be used in any laboratory where the method for specific factor-II assays or the Quick 1-stage prothrombin assay are available.