Studies on red cell glucose-6-phosphate dehydrogenase: evaluation of reference values

The analytical, intra-individual, inter-individual variation and reference values were determined for red cell glucose-6-phosphate dehydrogenase (G6PD). Different procedures for the conditions for storage of red blood cells and the preparation of haemolysates were investigated. A total of 2170 samples of blood were taken from apparently healthy persons-1212 males and 958 females--from randomly selected villages and city centres in the southern part of Turkey. Analytical variation, intra-individual variation and inter-individual variation were 8.67%, 32.8% and 31.8%, respectively. The mean (SD) for G6PD was 8.6 (3.3) IU/gHb. The index of individuality, 1.03, showed that the reference intervals could be used for diagnostic purposes. Whole blood or a red cell pellet could be stored in physiological saline for one week at 4 degrees C or -20 degrees with little loss of activity. Two of three different procedures for the preparation of haemolysate gave data that showed no statistical difference and were equally satisfactory.