Jh. Mcbride et Sb. Schotters, IMMUNOCHEMICAL EXTRACTION AND AUTOMATED MEASUREMENT OF PLASMA CREATINE-KINASE MB ISOENZYME AND CREATINE-KINASE MB2 ISOFORM, Journal of clinical laboratory analysis, 11(3), 1997, pp. 163-168
Measurement of creatine kinase MB (CKMB) and its isoforms CK-MB2 and C
K-MB1 are now applied in the diagnosis of acute myocardial infarction
(AMI). The most com mon approach for analysis includes RIA, IRMA, and
electrophoresis, all of which may be time-consuming. This study examin
es determination of CK-MB and CK-MB2 by a rapid immunochemical extract
ion method followed by an automated measurement for both analytes. The
automated method was sensitive to 2 U/L, linear to 180 U/L, and gave
excellent interassay precision (<10% CV). Interference studies indicat
ed that bilirubin, hemolysis, and lipemia caused analytical problems a
s did the presence of high activities of other CK isoenzymes, notably
CK-MM and CK-BB, requiring dilution of samples prior to analysis. Appl
ication of immunochemical extraction gave a reference interval of CK-M
B (0-2.5 U/L) and CK-MB2 (0.1-1.4 U/L) for blood donors (20-60 years),
peak levels for ruled-out AMI patients of CKMB (0.5-7.3 U/L) and CK-M
B2 (0.3-4.9), peak levels for ruled-in AMI patients of CKMB (80-174 U/
L) and CK-MB2 (80-155 Ui L). Coronary artery bypass patients (n = 24)
and all trauma patients (n = 14) also demonstrated elevations in CK-MB
and CK-MB2, whereas only five of the trauma patients demonstrated inc
reased CK-MB by IRMA. In patients (n = 7) having increased total CK an
d normal CK-MB by IRMA, the extraction assay for CK-MB and CK-MB2 yiel
ded increased values in all patients. This new approach to CK-MB and C
K-MB2 analysis can be performed within 30 minutes of sample receipt. (
C) 1997 Wiley-Liss, Inc.