Determination of creatine kinase MB activity with the Du Pont aca: interferences from the sample matrix.
During the last three years we and other have observed discrepancies between results for creatine kinase isoenzyme MB as measured with the mechanized ion-exchange chromatographic method in the Du Pont aca and those by other techniques. These observations prompted us to investigate the influence of the matrix on the Du Pont CK-MB assay. We conclude that, apart from possible interferences by CK-MM, CK-BB, and both types of macro CK, the aca will give apparent CK-MB activities that are directly related to protein concentration and inversely related to sodium chloride concentration. Practical consequences for the routine and emergency laboratories are: no diluted samples are allowed; application is restricted to samples from patients suspected of acute myocardial infarction which show upper-normal total CK activity; and multiple timed samples are run, in order to recognize the typical change in enzyme pattern with time.
D001322:Autoanalysis / Q000295:instrumentation*; D002852:Chromatography, Ion Exchange; D003402:Creatine Kinase / Q000097:blood* / Q000592:standards; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes; D009203:Myocardial Infarction / Q000097:blood*; D012709:Serum Albumin; D012710:Serum Albumin, Bovine; D012965:Sodium Chloride; D012996:Solutions; D013997:Time Factors
D007527:Isoenzymes; D012709:Serum Albumin; D012996:Solutions; D012710:Serum Albumin, Bovine; D012965:Sodium Chloride; D003402:Creatine Kinase