Diagnostic efficacy of a monoclonal antibody-based immunoenzymetric technique for quantitation of creatine kinase MB isoenzyme in serum.

The clinical usefulness of the Tandem-E CK-MB method (A) using two monoclonal antibodies to measure the intact cardiac specific creatine kinase isoenzyme (CK-MB) was evaluated against results obtained by Corning's electrophoretic fluorescence scanning method (B) and the DuPont aca mechanized column chromatographic method (C). In 95 patients suspected to have myocardial infarction, a total of 127 CK's with MB's were simultaneously determined by methods "A", "B", and "C". "C" produced a total of 16.5% (21 out of 127) false-negative or false-positive results. In contrast, CK-MB results obtained by "A" correlated very well with those determined by "B" (r = 0.97; N = 64). In addition, the clinical course of myocardial infarction as monitored by the measurement of CK-MB at various time intervals by both methods showed excellent parallelism. Furthermore, "A" was shown to be free of interference from the presence of macro CK type I and II. Also, the presence of increasing concentrations of CK-BB (up to 29 IU/L) did not alter the assay response of CK-MB in these serum samples. In conclusion, we found the Tandem-E CK-MB method to be sensitive (sensitivity = 94%) and specific (specificity = 96%).