[Sensitivity of creatine kinase and creatine kinase MB in myocardial infarction. Evaluation of a new optimized standard method (author's transl)].

In 70 patients with confirmed transmural myocardial infarction the sensitivity of creatine kinase and creatine kinase MB at different times after admission was investigated by 364 measurements. Beside the number of correctly positive results the optimized standard method hitherto used was compared with the new optimized standard method with N-acetylcystein as activator. During the first 12 hours after admission the percentage of correctly positive results was 64,4% for creatine kinase (GSH) and 86,7% for creatine kinase (NAC). The sensitivity of cretine kinase MB, however, was found to be 71,1% (GSH) and 86,7% (NAC). With respect to the poor specifity of creatine kinase the sensitivity of creatine kinase MB, especially when using the new optimized standard method is superior. Similar results were established 24 and 48 hours after admission. Creatine kinase MB only fails in detection of myocardial infarction if the stroke is older than 3 days or if the enzyme activity determination intervals are too long.