Reasonableness of use of the serum isoenzymes creatine kinase and lactate dehydrogenase for the diagnosis of myocardial infarction at a medical center.

At Charity Hospital of Louisiana at New Orleans, in 1978, there was considerable underuse of serum creatine kinase and lactate dehydrogenase isoenzymes for the diagnosis of myocardial infarction. Laboratory generation of creatine kinase isoenzyme tests for patients suspected of having had myocardial infarctions was only partially effective in correcting underuse. It unnecessarily generated some overuse. Appropriate modifications of this policy could improve performance. Additional, effective educational efforts are needed to improve reasonable use of laboratory tests. The study uncovered an unexpected problem in the laboratory--in a significant percentage of cases, results of indicated and ordered tests failed to appear in the charts.