SEMIQUANTITATIVE SCREENING TEST FOR G6PD DEFICIENCY DETECTS SEVERE DEFICIENCY BUT MISSES A SUBSTANTIAL PROPORTION OF PARTIALLY-DEFICIENT FEMALES

Abstract. Neonatal screening for G6PD deficiency has long been established in many countries. The aim of the study was to determine whether the routine semiquantitative fluorescent spot test could detect all cases of G6PD deficiency, including those cases with partial deficiency (residual red cell G6PD activity between 20-60 % of normal). We compared the results of G6PD screening by the semiquantitative fluorescent spot test and quantitative G6PD activity assay on a group of 976 neo-nates and 67 known female heterozygotes. The values for mean G6PD activity of G6PD-normal neonates and 293 healthy adult females were determined. There was no significant difference in the mean normal G6PD activity between the two racial groups in the neonates (669 Malays, 307 Chinese) and in the 293 healthy adult females (150 Malays, 143 Chinese) group. The values for the upper limits of total deficiency (20 % of normal residual activity) for neonates and adult females were 2.92 U/gHb and 1.54 U/gHb, respectively. The upper limits of partial deficiency (60 % of normal residual activity) were 8.7 U/gHb and 4.6 U/gHb respectively. The prevalence of G6PD deficiency among the male neonates was 5.1 % (26) by both the fluorescent spot test and the enzyme assay method. The G6PD activity levels of all 26 cases of G6PD-deficient male neonates were <20 % normal (severe enzyme deficiency). In the female neonate group, the frequency of G6PD deficiency was 1.3 % (6 of 472) b