Diagnostic Test for Myocardial Infarction

To the Editor.— The article by Saranchak and Bernstein, "A New Diagnostic Test for Acute Myocardial Infarction," (228:1251, 1974) raises important questions concerning the proposed method, which we believe must be answered before this procedure can be considered seriously. Although the authors state that quantitation of myoglobinuria is a "much more accurate diagnostic test for infarction than serum levels of glutamic oxaloacetic transaminase, lactic dehydrogenase, or creatine phosphokinase," they fail, in our opinion, to adequately substantiate their statement; hence, their hypothesis is unconvincing.1,2 The lowest myoglobin standard used (5 mg/100 ml) is unfortunately also at the critical decision point used as evidence by the authors for acute myocardial infarction; no information is provided for reproducibility of the assay technique at this critical level, or at levels lower than 5 mg/100 ml. Moreover, the data in Fig 1 indicate that there may be appreciable overlap between patients with arteriosclerotic heart