Assessment of Glucose-6-Phosphate Dehydrogenase Activity with a Delay

Abstract

Glucose-6-phosphate dehydrogenase (G6PD) is the most common and important enzyme deficiency in red blood cells. Lack of G6PD causes severe hyperbilirubinemia and increase the risk of kernicterus in neonates. A reliable diagnosis of G6PD status by spectrophotometry is costly, has a turn-around time of several hours, and requires good laboratory infrastructure; limitations that render routine G6PD testing by spectrophotometry unsuitable in most remote areas. In this study, we analyze different storage conditions to determine the best sample handling way during the pre-analytical step. G6PD activity was analyzed in blood samples from 10 non-G6PD-deficient adult males by the spectrophotometric quantitative method in different conditions of time and temperature. Results showed that sample hemolysate with glycerol 30% at 4oC (9.00±0.63) and heparin at 4oC (11.48±0.62) stabilize G6PD activity level within normal range 21 days after the initial dosage at t0. At 30oC, heparin stabilized G6PD activity level within a normal range (10.24±2.30) during 4 days. In sample hemolysate with 30% glycerol stored at -20oC, G6PD activity did not vary significantly during the 3 months of study. In a laboratory where frozen sample at - 20oC is possible, our results suggest that the best way of keeping samples for delay G6PD activity measurement was to prepare hemolysate with glycerol 30% and store at - 20oC. In a condition where the temperature is high, heparin anticoagulant seems to be more suitable for G6PD enzyme activity determination.