Objective: To explore the epidemiological distribution characteristics of glucose-6-phosphate dehydrogenase (G6PD) activity, incidence of G6PD deficiency in neonates and the cut-off values. Methods: About 1.44 million newborns in 10 districts of Zhejiang province from March 2015 to September 2017 were included in this study. Fluorescence analysis was used to determine the G6PD activity in dried blood spots. Those with initial screening positive results were recalled and confirmed by direct ratio of G6PD to 6PGD (6-phosphogluconate dehydrogenase) to confirm the diagnosis. The results were analyzed by using nonparametric and chi-square tests. Results: Significant differences of G6PD levels were found among the groups of different genders, gestational age, birth weight, blood sampling age, blood sampling season and districts (P＜0.01). The male incidence of G6PD deficiency was significantly higher than female incidence. In different regions of Zhejiang province, the highest prevalence was in Lishui (0.38%) and the lowest was in Zhoushan (0.11%), The trend of high prevalence in the south and low prevalence in the north was basically showed. When the cut-off value of G6PD activity ranged from 2.60 to 2.80 U/g Hb, the sensitivity of G6PD deficiency screening for male and female newborns was 100% and the Youden index was the highest (about 0.99). Conclusion The level of G6PD activity may be relevant to the factors of population group and period. The incidence of G6PD deficiency may be affected by different genders and different regions. The cut-off values for screening may initially set at 2.60 U/g Hb and 2.80 U/g Hb for male and female respectively.

OBJECTIVE: To explore effects of different delivery and storage conditions on concentrations of amino acids and carnitines in neonatal dried blood spots (DBS), so as to provide evidence for improving accurate and reliable detection by tandem mass spectrometry. METHODS: A total of 1 254 616 newborn DBS samples in Newborn Screening Center of Zhejiang Province were delivered and stored at room temperature (group A, RESULTS: The concentrations of amino acids and carnitines in the three groups were skewed, and the differences in amino acid and carnitine concentrations among groups were statistically significant (all CONCLUSIONS Cold-chain logistics system and storage in low temperature and low humidity can effectively reduce degradation of some amino acids and carnitines in DBS, improve the accuracy and reliability of detection, and thus ensures the quality of screening for neonatal metabolic diseases.
Amino Acids/analysis* ; Carnitine/analysis* ; Dried Blood Spot Testing/standards* ; Humans ; Humidity ; Infant, Newborn ; Neonatal Screening ; Reproducibility of Results ; Specimen Handling/standards* ; Tandem Mass Spectrometry ; Temperature ; Time Factors