Diagnostic performance of red cell indices in detecting iron deficiency and iron deficiency anemia among rural adolescent girls aged 14–19 years in Nagpur District

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.