Application of genetic screening processor in screening neonatal glucose-6-phosphate dehydrogenase deficiency

To evaluate the performance of genetic screening processor (GSP analyzer) in neonatal screening for glucose-6-phosphate dehydrogenase (G6PD)deficiency. The accuracy and precision of GSP analyzer was evaluated with the control materials from National Center for Clinical Laboratories and the low and high quality G6PD control kit (fluorescence analysis). GSP analyzer and semi-automatic fluorescence immunoanalyzer (1420 analyzer) were simultaneously used to detect 2622 neonatal screening samples and 41 confirmed samples to analyze the correlation and consistency of the test results; 78 floating samples and 78 non-floating samples were detected to compare the result. A total of 1 100 384 neonatal screening samples from January 2017 to December 2018 and 855 856 neonatal screening samples from January 2019 to December 2020 were detected with 1420 analyzer and GSP analyzer, respectively. Referring to the percentile method and the expert consensus, the new cut-off value of GSP analyzer for G6PD deficiency in screening was established. The relative bias of GSP analyzer in detecting G6PD was 0.71%-4.23%; the intra assay precision was 4.34%-4.91%, the inter assay precision was 0.85%-2.12%, and the total coefficient of variation was 5.44%-5.72%. There was a significant positive correlation between G6PD activity detected by GSP analyzer and 1420 analyzer (=0.740, <0.01). Forty-one clinical confirmed patients were identified by both 1420 analyzer and GSP analyzer (=0.945). The G6PD activity in floating dry blood spots detected by 1420 analyzer was significantly lower than that in non-floating dry blood spots (<0.05), but there was no significant difference in G6PD activity between floating and non-floating dry blood spots detected by GSP analyzer (>0.05). The sensitivities of GSP analyzer and 1420 analyzer in screening G6PD deficiency were both 100.00%, and the specificities were both more than 99.80%. Compared with 1420 analyzer, the positive predictive value, positive rate and prevalence of G6PD deficiency detected by GSP analyzer were increased, and the false positive rate was decreased (all <0.01). The new cut-off value was 26.1 U/dL for male and 29.1 U/dL for female according to the 99.1% percentile of the population. GSP analyzer has better detection performance with high automation, efficiency and throughput, which can be used in large-scale screening for neonatal G6PD deficiency.