Diagnostic Accuracy of Mentzer Index in Diagnosis of Iron Deficiency Anemia Taking Serum Feritin as The Gold Standard

Background: Iron deficiency anemia is a common childhood nutritional disorder. In low-resource settings, inexpensive and easy screening tools are essential. The Mentzer index from complete blood counts is a potential substitute for serum ferritin, the gold standard for diagnosis. Objective: To determine the diagnostic accuracy of Mentzer index in diagnosis of iron deficiency anemia, taking serum ferritin as the gold standard. Study Design: Cross-sectional validation study. Duration and Place of Study: Conducted from August 2024 to January 2025 at the Department of Pediatric Medicine, Combined Military Hospital, Rawalakot. Methodology: A total of 210 children aged 1–5 years with microcytic hypochromic anemia were enrolled. The Mentzer index (MCV/RBC count) was calculated, with a value >13 indicating IDA. Serum ferritin levels <40 ng/mL confirmed the diagnosis. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were computed. Results: Among 210 children, the Mentzer index showed a sensitivity of 89.1%, specificity of 73.2%, diagnostic accuracy of 76.7%, PPV of 48.2%, and NPV of 96%. Stratified analysis revealed high sensitivity and NPV in rural children and males, with variability across other subgroups. Conclusion: The Mentzer index is a useful, sensitive, and low-cost screening tool for diagnosing iron deficiency anemia in children.