Spectrophotometric Modification of the TAMe Assay for "Prothrombin"

Abstract

The purpose of this communication is to describe a new "prothrombin" assay and to report results of its use in the control of anticoagulant therapy in 1,414 patients. The assay is a spectrophotometric modification of the original TAMe procedure and is based on the esterolytic action of thrombin on p-tosyl-l-arginine methyl ester (TAMe). The assay was performed in parallel with the one-stage, two-stage, and Thrombotest assays in patients during anticoagulant therapy induction, maintenance (long and short-term), and recovery periods, the results closely paralleling those of the two-stage procedure. Because of (1) the uniform reproducibility of its results, (2) the simplicity with which it can be performed, and (3) its ready adaptability to routine clinical use, the authors have found it the most satisfactory "prothrombin" assay they have used.