Publication: Comparison of fluorescent spot test against quantitative enzyme assay for detection of glucose-6-phosphate dehydrogenase deficiency
Date
2022
Authors
Halim, Sarah Abdul
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Abstract
Objectives: Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most
common enzymopathy in the world. Some countries have practiced fluorescent spot test
(FST) as a neonatal screening method since the 1980s. However, FST has its own
limitations. Quantitative assays such as the careSTARTTM BioSensor1 have been
demonstrated to be able to overcome some of these limitations. The objectives of this
study are to compare the performance of FST with BioSensor1 in detecting G6PD
deficiency in neonates and to verify the reference range of G6PD level for cord blood
using BioSensor1.
Methods: This study was a cross sectional study involving 455 neonates born in Hospital
Universiti Sains Malaysia (Hospital USM), Kelantan, Malaysia beginning June 2020 until
December 2020. Two millilitres of cord blood were taken in EDTA bottles to be analysed
with BioSensor1 and dried cord blood spots on filter paper were sent for FST to determine
the levels of G6PD. Demographics data and birth characteristics were taken from labour
room records. Data was recorded and analysed using the Statistical Package for the Social
Software (SPSS) version 27. P-value less than 0.05 were considered as significant.
Results: The sensitivity of FST was 91% whilst its specificity was 97% at 30% cut-off
G6PD activity level. In contrast, at 60% cut-off G6PD activity level, the sensitivity
drastically decreased to 29% whilst the specificity was 100%. The overall prevalence of
G6PD deficiency was 5.1% and 17.8% for FST and Biosensor1 respectively,
demonstrating a drastic difference between the two tests (p < 0.001). The mean G6PD
level for term neonates was 6.84 U/gHb whilst for preterm neonates was 6.63 U/gHb.
Using independent T-Test, there was no significant difference in the mean G6PD levels between term and preterm neonates. There was also no significant association between
different gestational age groups, maternal blood group and birthweight with mean G6PD
level when tested using one way ANOVA test.
Conclusions: FST has low sensitivity at 60% cut-off G6PD level. This cut-off level
reflects intermediate G6PD activity, hence FST missed a significant proportion of G6PD
intermediate individuals in our study. At the same time, the prevalence of G6PD
deficiency significantly increased with the use of BioSensor1. Gestational age,
birthweight and maternal blood group do not have significant association with G6PD
level. In a budget constrained facility, it is recommended to use quantitative enzyme assay
to screen female neonates and to use FST for male neonates especially in areas where
G6PD deficiency is prevalent.
Description
Keywords
G6PD deficiency , fluorescent spot test