CARDIAC TROPONIN-I SHOULD REPLACE CKMB FOR THE DIAGNOSIS OF ACUTE MYOCARDIAL-INFARCTION

Cardiac troponin I (cTnI) has been reported to be a highly specific ma rker for cardiac injury. We investigated the performance of this assay in patients admitted to a coronary care unit for suspected acute myoc ardial infarction (AMI), patients with extensive skeletal muscle damag e, marathon runners and as a routine diagnostic test over a four week period. cTnI proved to be as sensitive a marker for AMI as creatine ki nase/MB isoenzyme (CKMB) in patients admitted to the coronary care uni t. In 10 patients with a proven AMI, the cTnI remained elevated from 6 9 to 183h with a median time of 127h. Cardiac troponin I had superior specificity to CKMB in patients with skeletal muscle damage. It was ve ry useful in these patients to confirm or exclude concurrent myocardia l damage. In routine diagnostic use, cTnI had greater efficiency than CKMB to classify patients as having an AMI. Consequently cTnI should r eplace CKMB as a marker for AMI.