The medium-fluorescence reticulocyte ratio is an independent predictor of G6PD deficiency neonates.

Objective: G6PD deficiency is a potentially life-threatening condition in neonates presenting with hyperbilirubinemia. This study aims to identify clinical and laboratory predictors of G6PD deficiency in neonates presenting with hyperbilirubinemia.

Methods: This was a retrospective study of 227 term neonates admitted to Heyuan People's Hospital from January 2019 to October 2023. Hematological parameters and bilirubin were compared between those with G6PD deficiency and those with normal G6PD.

Results: Term neonates with G6PD deficiency had higher levels of total bilirubin, indirect bilirubin, mean corpuscular volume, mean corpuscular hemoglobin, immature reticulocyte fraction, high-fluorescence reticulocyte ratio, medium-fluorescence reticulocyte ratio, and content of reticulocytes than those with normal G6PD, but lower levels of red blood cells, hemoglobin, hematocrit, and low-fluorescence reticulocyte ratio. Medium-fluorescence ratios (OR = 1.291, P = 0.028) independently predicted G6PD deficiency in neonates. The optimal cut-off value for medium-fluorescence ratios was > 18.55%. The area under the curve for diagnosing G6PD deficiency was 0.924 (95% confidence interval: 0.886-0.962, P < 0.0001), with a sensitivity of 82.6% and specificity of 86.2%.

Conclusions: MFR emerged as a potentially valuable predictor for G6PD deficiency in neonates.