Clinical effectiveness of the Du Pont aca measurement of creatine kinase MB in serum from patients in a coronary-care unit.
We evaluated the clinical effectiveness of measuring creatine kinase (CK; EC 2.7.3.2) isoenzyme MB and lactate dehydrogenase (LD; EC 1.1.1.27) isoenzymes in diagnosis of acute myocardial infarction. We used an agarose electrophoresis method to measure CK and LD isoenzymes and the Du Pont aca column method to measure CK-MB. Serial blood specimens were drawn from 100 patients consecutively admitted to our Coronary Care Unit. Because of the low diagnostic specificity for CK-MB measurements by both agarose electrophoresis and the discrete-analysis method, as compared with reported values, we re-evaluated our isoenzyme data by using Receiver Operating Characteristic curves. Such analysis of the data established optimal decision levels of greater than or equal to 25 U/L and greater than or equal to 18 U/L plus greater than or equal to 6% of total CK for serum CK-MB measured by the agarose electrophoresis and the aca methods, respectively, and an optimal decision level of greater than or equal to 0.92 for the ratio of LD 1/2 measured after agarose electrophoresis. At these decision levels we obtained a sensitivity of 100%, 100%, and 95% and a specificity of 94%, 92%, and 90% for CK-MB (agarose electrophoresis), CK-MB (aca), and the LD 1/2 ratio, respectively.
D001322:Autoanalysis; D004796:Clinical Enzyme Tests / Q000379:methods*; D003325:Coronary Care Units; D003402:Creatine Kinase / Q000097:blood*; D004587:Electrophoresis, Agar Gel; D006801:Humans; D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase / Q000097:blood; D009203:Myocardial Infarction / Q000175:diagnosis*
D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase; D003402:Creatine Kinase