Clinical evaluation of different principles of CK-MB determination.

Seven methods commercially available involving different principles for determination of creatine kinase (E.C. 2.7.3.2) isoenzyme MB were compared. The methods employ quantitative electrophoresis, column chromatography, batch chromatography, and antibody inhibition techniques. Blood from 100 patients suspected of acute myocardial infarction was used to test the following factors: sensitivity, linearity, precision, accuracy, simplicity, and diagnostic comparability. The analytical quality of all the techniques investigated was almost satisfactory, and only minor differences were found in linearity and precision. The diagnostic quality was, however, somewhat limited. The number of positive and negative results varied significantly. The reference value given by the manufacturers did not agree, and each laboratory must establish its own reference ranges.