title: Creatine kinase and creatine kinase B-subunit activity in serum in cases of suspected myocardial infarction.
abstract: We evaluated a diagnostic strategy by studying 481 patients suspected of having had an acute myocardial infarction; the prevalence of infarction by independent criteria was 0.43. This strategy is based on the sequential application of: (a) clinical criteria; (b) total creatine kinase determinations in two serum samples drawn within 10 to 20 h of the onset of acute symptoms; and (c) creatine kinase B-subunit (S-CK B) determinations after immunoinhibition with antibodies to creatine kinase M-subunit in the reaction medium in all samples found to have increased total creatine kinase activity. Discrimination limits of 150 U/L total creatine kinase for women and 200 U/L for men gave a diagnostic sensitivity of 0.99. Activities less than these limits in samples identified 68% of the 274 non-infarct cases (posterior probability of a negative result of 0.99) within 20 h. Subsequent determination of S-CK B in 292 patients who were positive by the discrimination limits for total creatine kinase verified myocardial infarction in 99% of 207 cases for which S-CK B exceeded the discrimination limit of 12 U/L. The strategy excluded 98% of all non-infarct cases at a posterior probability of 0.99.
mesh_terms: D000410:Alanine Transaminase / Q000097:blood; D001219:Aspartate Aminotransferases / Q000097:blood; D004796:Clinical Enzyme Tests; D003402:Creatine Kinase / Q000097:blood*; D003937:Diagnosis, Differential; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase / Q000097:blood; D008297:Male; D009203:Myocardial Infarction / Q000175:diagnosis*; D012737:Sex Factors; D013997:Time Factors
chemical_list: D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D003402:Creatine Kinase