Stability of erythrocytic enzymes for screening tests.

We investigated the stability of certain erythrocytic enzymes as assayed qualitatively by fluorescence spot tests. Preservation of the activities of glucose6-phosphate dehydrogenase (GPD), pyruvate kinase (PK), triose phosphate isomerase (TPI), glutathione reductase (GTD), and NADH diaphorase (ND) in heparin, glucose-EDTA, or Alsever’s solution was studied at -20#{176}C and 30#{176}C. In Alsever’s solution, GPD, PK, GTD, and TPI are stable for 25 days at 30#{176}C, whereas ND is stable for only 10 days at either -20#{176}C or 30#{176}C. The stabilizing action of Alsever.s solution permits either large population sampling before testing or a sufficient time period for transport of samples to a central laboratory for processing.