Analysis of the diagnostic efficacy of hemoglobin capillary electrophoresis for thalassemia in children under 2 years old in Southern Fujian (Minnan) Region, China

To establish age-specific diagnostic cut-off values for HbF and HbA 2 in children under 2 years in Southern Fujian, China, across α-thalassemia group(carriers and patients),β-thalassemia group(carriers), and a negative control group, and evaluate their diagnostic efficacy for precise thalassemia screening. A retrospective analysis was conducted on 1,072 children under 2 years old. Participants were divided into α-thalassemia group(carriers and patients,331 samples), β-thalassemia group(carriers,220 samples), α+β-thalassemia group(10 samples), and negative control groups (511 samples), and further stratified into three age groups: 0–6 months (172 samples), 7–12 months (532 samples), and 13–24 months (368 samples). ROC curve analysis determined optimal cut-off values for HbF and HbA 2 , with AUC, sensitivity, and specificity calculated. Normal reference ranges were also analyzed. In the negative control group, mean HbA 2 and HbF varied significantly with age. For β-thalassemia, optimal HbA 2 cut-offs were 2.6% (0–6 months, AUC=0.849, sensitivity 80.6%, specificity 85.9%), 3.15% (7–12 months, AUC=0.979, sensitivity 97.9%, specificity 98.8%), and 3.7% (13–24 months, AUC=0.990, sensitivity 98.9%, specificity 98.7%). Optimal HbF cut-offs were 10.1% (0–6 months, AUC=0.720), 4.75% (7–12 months, AUC=0.920), and 2.35% (13–24 months, AUC=0.931). For α-thalassemia, HbA 2 cut-offs showed limited diagnostic value (AUC ≤0.667). HbF and HbA 2 levels are significantly influenced by age. Age-stratified cut-off values for HbA 2 demonstrate excellent diagnostic efficacy for β-thalassemia and can serve as primary screening indicators. For α-thalassemia, HbA 2 measurement alone is insufficient, highlighting the need for complementary testing methods to improve diagnostic accuracy.