To the Editor.
—The cardiac isoform of troponin I (TnI) has been touted as 100% specific for myocardial injury.1-3 While serving on the consult service of a large teaching hospital, we occasionally have evaluated patients with chest pain and elevations of TnI levels in whom we were unable to find any evidence of myocardial injury. We reviewed consecutive patients evaluated at our hospital between January and June 1996 who had elevated serum TnI levels to determine the specificity of this assay for myocardial injury in clinical practice.Troponin I levels were obtained as part of routine clinical practice when myocardial injury was suspected, and 343 patients had 1 or more TnI values of 1.0 ng/mL or greater. Cardiac TnI was measured on the Stratus II analyzer (Baxter Dade, Miami, Fla) with a commercial immunoassay procedure that uses 2 monoclonal antibodies directed against different epitopes on TnI.4Of the
Wright SA, Sawyer DB, Sacks DB, Goldhaber SZ. Elevation of Troponin I Levels in Patients Without Evidence of Myocardial Injury. JAMA. 1997;278(24):2144. doi:10.1001/jama.1997.03550240034028