Immunoinhibition and automated column chromatography compared for assay of creatine kinase isoenzyme MB in serum.
We examined sera from six different groups of patients for CK-MB activity by means of two commercially available tests, an immunoinhibition method (E. Merck) and the CK-MB test as used with the aca (Du Pont). In the first group of patients (suspicion of myocardial infarction) the correlation between the two methods was good: r = 0.9191, y = 1.068x -- 0.888, x = 18.7 U/L, y = 19.0 U/L. In the second group, patients with high adenylate kinase activity, no interference was detectable on the aca, whereas the immunoinhibition method yielded falsely high CK-MB values. The third group consisted of persons with macro-CK-BB in their serum. In the immunoinhibition test these patients usually showed a high CK-MB:total CK ratio, whereas such results were rarely found for the aca. The fourth group, patients with a different electrophoretic mobility of their CK-isoenzymes (migration of an active band towards the cathode), were detected by the immunoinhibition method (high ratio of CK-MB to total CK), but not with the aca. In the presence of free CK-BB (group five) the immunoinhibition test resulted in "falsely" high CK-MB values, whereas CK-BB was retained on the column of the aca. In skeletal muscle diseases (group six) results by the two methods differed, values for CK-MB on the aca being much higher. It was demonstrated experimentally that this was due to CK-MM with altered surface charge.
D000263:Adenylate Kinase; D003402:Creatine Kinase / Q000097:blood*; D006801:Humans; D007527:Isoenzymes; D009135:Muscular Diseases / Q000097:blood*; D009203:Myocardial Infarction / Q000097:blood*; D011933:Reagent Kits, Diagnostic; D012016:Reference Values
D007527:Isoenzymes; D011933:Reagent Kits, Diagnostic; D003402:Creatine Kinase; D000263:Adenylate Kinase