The clinical utility of CK-MB measurement in patients suspected of acute coronary syndrome

Background: This study aims to assess the clinical utility of CK-MB measurement in patients suspected of acute coronary syndrome (ACS). Methods: All CK-MB and troponin T measurements performed <1 h apart during the study period were obtained and analyzed for concordance. A total of 1214 cases with discordant biomarkers results were found. Retrospective review of electronic health records (EHRs) was performed to assess the clinical impact, if any, of the discordant biomarkers results. Results: In 401 cases, CK-MB concentrations were increased whereas troponin T concentrations were negative at <0.01 ng/ml. In this group, clinical interpretations included, rhabdomyolysis, demand ischemia, and drug intoxication. No additional investigations for ACS were conducted in this group. Among the remaining 813 cases, troponin T concentrations were increased in the presence of a normal CK-MB result. In this group, the discordant normal CK-MB lowered suspicion for ACS in only 22 cases (2.7%). Most common interpretations for isolated positive troponin were demand ischemia and impaired renal function. In most cases, discordant CK-MB results were not considered a significant finding. Conclusions: In the setting of suspected ACS, CK-MB has limited clinical impact when contemporary troponin assay results are available.