Table 1. isoenzyme Assay Values for Patients Suspected of Having AMI

2002 CLINICAL CHEMISTRY, Vol. 32, No. 10, 1986 AMI and non-AM! categories by EMBRIA-cK and did not require grouping into intermediate or equivocal categories as was required by Adan et al. The maximum diagnostic efficiencies, based on the optimum reference ranges established, were: for EMBRIA-CK, 98.7%; for LD-1, 90%; and for LD-1/ total LD, 86.3%. Specific CK-MB tests have also been found to provide satisfactory answers for other groups for which the B-unit test was not satisfactory. DePuey et al. (3), in 1983, used several criteria, including electrophoresis and radionuclide ventriculography, and reported achieving 97% accuracy with EMBRJAcx in diagnosing pen-operative infarction-higher than achieved with electrophoresis. The use of a CK-MB-specific test has been found to classiI r correctly patients with mild or slowly evolving infarcts (4). I recently participated in a study of blunt chest-trauma patients; patients with high mortality and extended hospitalization were found to have increased immunometrically measured CK-MB concentrations as compared with those with no complication and short hospitalization periods. There is no “gold standard” for AMI for living patients, but one is available after death. Autopsy studies have consistently disclosed high failure rates in diagnosing AMI (5). McQueen et al. (6) have shown CK-MB assay to be a very reliable indicator of AM!, based on autopsy studies. This should encourage laboratorians to investigate further the utility of newly available CK-MBspecific tests. Results obtained so far with immunometric tests are encouraging and have been found useful for patients who are otherwise difficult to diagnose. I believe that confusion related to isoenzyme testing will diminish and cardiologists’ confidence in laboratory results will increase as CKMB-specific tests become more acceptable in the laboratory environment. In some laboratories, the need for a high degree of automation may preclude the use of CK-MB-specific tests. Currently, only B-unit immunoinhibition and mini-column methods are sufficiently automated to satisf ’ this need. These methods have a lower diagnostic efficiency than CK-MB-specific methods. On the other hand, automated LD-1 and total U) procedures are accurate. Reliance on LD-1 or LD1/total LD ratio rather than so-called CK-MB results may be appropriate in this situation.