G6PD enzyme activity in normal term Malaysian neonates and adults using a OSMMR2000-D kit with Hb normalization

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the commonest causes of neonatal jaundice in Malaysia. Screening of cord blood for G6PD deficiency by the semiquantitative fluorescent spot test (FST) is performed in Malaysia but this test can miss cases of partial G6PD deficiency. The OSMMR-D kit assay measures G6PD activity and hemoglobin (Hb) concentration, allowing direct expression of results in U/gHb. We evaluated this method and established the normal range for G6PD activity in normal term neonates and adults. EDTA blood from 94 neonates and 295 adults (age 15-59 years old) with normal Hb and FST were selected. The normal means for G6PD activity for neonates and adults were 12.43 +/- 2.28 U/gHb and 9.21 +/- 2.6 U/gHb, respectively; the reference ranges for normal G6PD activity in neonates and adults were 10.15-14.71 U/gHb and 6.61-11.81 U/gHb respectively. There were no significant differences in mean normal G6PD activity between the Malays and Chinese racial groups or between genders. The upper and lower limit cut-off points for partial deficiency in neonates were 7.4 U/gHb (60% of the normal mean) and 2.5 U/gHb (20% of the normal mean), respectively. For adults, the upper and lower limit cut-off points for partial deficiency in adults were 5.52 U/gHb (60% of the normal mean) and 1.84 U/gHb (20% of the normal mean), respectively. The quantitation of G6PD enzymes using this OSMMR-D kit with Hb normalization was simple since the Hb was analyzed simultaneously and the results were reproducible with a CV of less than 5%.