lsoenzymesby Useof the “Diagnostest”

A method is described for measuring serum lactic dehydrogenase iso-enzymes by use of a commercial electrophoresis system. Six samples are simultaneously electrophoresed on cellulose acetate plates to separate the five isoenzymes, which are made visible by overlaying and incubating the electrophoresed plate with another plate saturated with lactate, phen. azine methosulfate, and INT (a tetrazolium dye). The pattern is qualita-tively assessed, or the plates are made transparent with dimethylsulfoxide-propanol and the isoenzymes measured densitometrically. The normal range for each isoenzyme, determined on 39 nonmedicated, nonfasting men and women, agrees with reported values. Duplicate plates are ob-tained for each serum analyzed. The entire procedure requires 2 h. Additional Keyphrases normal values Starch or agar gel is commonly used as the sepa-ration medium for electrophoretically fractionat-ing LDH1 (lactic dehydrogenase; E.C. 1.1.1.27; L-lactate: NAD oxidoreductase) isoenzymes in serum (1-6). Gel media are tedious to prepare, and sub-sequently dry and crack if improperly stored. Also, the ultraviolet light- or fluorescence-scanning systems needed for quantification are often too elaborate for routine use. A complete electrophoretic system (“DIAG