An evaluation of the immunochemical LD-1 method in routine clinical practice

We report our extended clinical experience with the use of an immunochemical method for LD-1 assay in 260 unselected, consecutive patients admitted with the clinical suspicion of recent myocardial infarction (M.I.). We determined on every patient total creatine kinase (CK) and total lactate dehydrogenase (LD) enzyme activity, and performed electrophoresis for LD isoenzymes as well as the heart-specific band of creatine kinase (CK-MB). An immunochemical assay for the heart-specific isoenzyme of LD (LD-1) was also performed. The timing of the samples was determined by the clinicians according to routine clinical protocols in the coronary care units. The diagnosis was based on the usual combination of clinical, electrocardiographic (EKG) and laboratory findings, and was arrived at independently by the clinician. In this extended series, the overall efficiency of the immunochemical LD-1 assay for the proper classification of the patients according with the discharge diagnosis was 92%. For CK-MB it was 90%, for EKG 77% and for LD electrophoresis 76%. The immunochemical LD-1 assay required no special instruments or highly skilled technicians and is probably the method of choice for the stat evaluation of recent M.I.