RDW data.

Iron deficiency anemia (IDA) remains a major public health concern among adolescent girls in rural areas. This study assessed the diagnostic performance of red cell distribution width (RDW) and hemoglobin (Hb) in detecting IDA. A cross-sectional study was conducted among 221 healthy rural adolescent girls (14–19 years) randomly selected from 24 government schools across 18 villages under four primary health centers in Nagpur district, Maharashtra (CTRI/2020/01/023035). Venous blood samples were analyzed for hematological parameters, and ROC curve analysis determined optimal diagnostic cut-offs. The iron-deficient group showed significantly lower MCV (75.3 vs. 84.5 fL, p < 0.001), MCH (24.3 vs. 28.1 pg, p < 0.001), and median Hb (10.9 vs. 12.0 g/dL, p < 0.01) compared to iron-sufficient girls. RDW was higher (16.3% vs. 14.9%, p < 0.01) and serum ferritin lower (6.8 vs. 30.95 μg/L, p < 0.01) in IDA cases. ROC analysis revealed an AUC of 65% for RDW alone, with optimal cut-off >16.9% (sensitivity 39.5%, specificity 82%). Lowering the cut-off to >16.7% improved sensitivity to 44%. The combined Hb ≤ 10.3 g/dL and RDW ≥ 16.4% showed superior performance with 93% sensitivity, 75% specificity, and 89% accuracy (AUC 72%), though not significantly different from RDW alone. While RDW alone has moderate diagnostic value, its combination with Hb significantly enhances IDA detection in adolescent girls. This simple, cost-effective two-parameter approach (Hb ≤ 10.3 g/dL + RDW ≥ 16.4%) offers an efficient screening tool for resource-limited rural settings, where advanced diagnostics are often unavailable. The findings support using routine hematological parameters for early IDA identification in vulnerable populations.