Serum Lactate Dehydrogenase Isoenzyme and Total Lactate Dehydrogenase Values in Health and Disease, and Clinical Evaluation of These Tests by Means of Discriminant Analysis

Abstract

Data concerning the lactate dehydrogenase isoenzyme and total lactate dehydrogenase values for normals and various disease states are presented. Analysis of some of these data by means of a computerized discriminant function program indicated that the above enzyme assays are useful in the differential diagnosis of infectious hepatitis, infectious mononucleosis, myocardial infarction, and lung cancer. The usefulness of these assays for other diagnostic situations was not investigated by this method. The use of discriminant analysis as an aid to laboratory medicine is discussed and illustrated with respect to the enzyme values in the following ways: (1) the reasons and the method for using discriminant analysis; (2) its application for evaluating the diagnostic usefulness of a test or group of tests; (3) its application for the differential diagnosis of a particular clinical state; and (4) the limitations of discriminant analysis for these applications.