Determination of LDH isoenzymes.

THE DETERMINATION of serum lactate dehydrogenase isoenzymes holds out numerous possibilities in the clinical laboratory aside from the obvious applications in myocardial immfarction and liver disease. An excellent review on different patterims obtained in various diseases can be found in an article by Wr#{243}blewski (1). Richterich et at. (2) describe the patterns found in humami tissues. Nevertheless, the utilization of the assay is progressing at a rather slow pace. The major drawbacks to the existing methods are their complicated procedures, and the relative unstability of most of time reagents. The methods emmiploying cellulose acetate paper avail themselves of the reduction of blue tetrazolium and obviously require a 2-stage chenmical reactiomm. The problem of fading, as well as the number of unstable reagents, makes these methods extremely difficult to handle on a day-to-day basis (3). Time classic methods utilizing agar as the supporting medlia and blue tetrazolium for color development are too cumbersome for the average clinical laboratory. The introduction by G. K. Turmier Associates (4) of a complete system for determining the isoemmzymes of lactate dehydrogenase by thingel electrophoresis and measuring the fluorescence of nicotumamide adenine dinucleotide (NADH) showed promise for simplification and improvemeimt. Yet, the preparation of the agar plates both for electrophoresis and reagemmts complicated the procedure. From the experience gained witim the Turner apparatus, it became obvious that the ideal situatiomi would be an adaptation of the fluorometric system to cellulose acetate strips.