Troponin T Levels and Abciximab Therapy in Unstable Angina

To the Editor: The accuracy of measurements of troponin T and creatine kinase MB fraction (CK-MB) is central to the results of the c7E3 Fab Antiplatelet Therapy in Unstable Angina (CAPTURE) study reported by Hamm et al. (May 27 issue). 1 The authors state that “all serum samples were stored at –20°C or lower and transported to a central laboratory, where they were stored at –80°C until they were analyzed.” It is recognized that total creatine kinase activity decreases steadily when stored at a temperature of –30°C (there is a decline in activity of 8.3 percent after four weeks). 2 A similar . . .