Thin-LayerAgaroseElectrophoresisof LactateDehydrogenase Isoenzymesin Serum: A Note on the Methodof Reportingand on the LactateDehydrogenaseIsoenzyme-1/Isoenzyme-2 Ratio in Acute MyocardialInfarction

We assessed the clinical efficacy of a thin-layer agarose electrophoresis assay for lactate dehydrogenase isoen-zyme estimation in the diagnosis of acute myocardial in-farction. From a population of 228 patients admitted to the Coronary Care Unit with suspected acute myocardial in-farction, all 101 positive cases (confirmed by clinical presentation and electrocardiographic changes) were correctly identified with lactate dehydrogenase isoen-zyme- 1 percentage of total activity above the reference range and with a lactate dehydrogenase isoenzyme- 1/ isoenzyme-2 ratio of 0.76 or above. This ratio was between 0.45 and 0.74 for 250 healthy subjects. No falsely negative, but 12 falsely positive results were obtained from this Coronary Care Unit population, to give a sensitivity of 100 % and a specificity of 90.5 % for the ratio test