Diagnostic accuracy of hematological indices and logistic regression for β-thalassemia carrier screening in children.

This study aimed to evaluate whether β-thalassemia trait can be diagnosed without hemoglobin electrophoresis by assessing the diagnostic performance of complete blood count parameters (mean corpuscular volume [MCV], red cell distribution width [RDW], and Mentzer index), transferrin saturation, and derived indices in anemic pediatric patients, using hemoglobin electrophoresis as the reference standard. A retrospective observational cross-sectional study was conducted on 558 children (1 month-18 years) who underwent hemoglobin electrophoresis between 2019 and 2025. Hematological parameters, iron status, and family history were analyzed. Patients were classified as normal electrophoresis, β-thalassemia carrier, major, or intermedia according to guidelines. Receiver operating characteristic analysis determined cutoffs, and a logistic regression model was developed and validated (80% training, 20% testing, Hosmer-Lemeshow P = .62, bootstrap n = 1000). Among 550 analyzed patients, β-thalassemia carrier prevalence was 25.1%. Carriers showed significantly lower MCV (57.07 ± 4.93 vs 70.08 ± 7.08 fL) and higher RDW (18.57 ± 2.62 vs 15.00 ± 2.39%) compared to controls (P < .001). The Mentzer index (≤11.97) achieved optimal performance with 93.5% sensitivity and 88.1% specificity. A combined diagnostic rule using 3 parameters (MCV ≤ 62.45 fL, Mentzer ≤ 11.97, and RDW > 16.45%) markedly improved specificity to 98.3% and positive predictive value to 93.5%. The logistic regression model achieved 95.5% overall accuracy. Positive family history was significantly associated with carrier status (23.1% vs 7.5%, P < .001). Simple complete blood count-derived indices offer reliable, cost-effective screening for β-thalassemia carriers, potentially reducing unnecessary electrophoresis testing by 60% to 70% in resource-limited settings.