Comparative Diagnostic Accuracy of Clinical Pallor at Different Anatomical Sites for Detecting Anemia in Pregnant...

Background Anemia during pregnancy remains a major public health problem in low-resource settings. Although hemoglobin estimation using portable devices such as the HemoCue® Hb 201 System (HemoCue AB, Ängelholm, Sweden) is reliable, clinical assessment of pallor continues to be widely used in primary care because of its simplicity, feasibility, and low cost. However, evidence comparing the diagnostic accuracy of pallor at different anatomical sites among pregnant women is limited. Objective This study aimed to determine and compare the diagnostic accuracy of clinical pallor at different anatomical sites for detecting anemia among pregnant women using HemoCue® hemoglobin estimation as the reference standard. Methods A cross-sectional diagnostic accuracy study was conducted among 186 pregnant women attending the Rural Health Training Centre (RHTC) in Barwala, Delhi. Clinical pallor was assessed under natural light at the palpebral conjunctiva, nail bed, palm, and palmar crease. Hemoglobin concentration was measured using HemoCue® as the reference standard. Diagnostic accuracy measures, including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), likelihood ratios, and Cohen's kappa (κ), were calculated for detecting anemia (hemoglobin <11 g/dL). Results Among the 186 pregnant women enrolled, 139 (74.7%) were anemic based on HemoCue® hemoglobin estimation. Palpebral conjunctival pallor demonstrated the highest sensitivity (98.6%) and specificity (93.6%), with excellent agreement (κ = 0.92). Nail bed pallor showed a sensitivity of 81.3% and a specificity of 42.6%, while palmar pallor demonstrated a sensitivity of 71.9% and a specificity of 78.7%. Palmar crease pallor had the lowest sensitivity (46.0%) but a specificity of 78.7%. Palpebral conjunctival pallor also showed the highest positive LR (LR+; 15.45) and the lowest negative LR(LR-; 0.02). Conclusion Palpebral conjunctival pallor demonstrated the highest diagnostic accuracy for detecting anemia in pregnant women and may serve as a reliable screening method in primary care settings where hemoglobin estimation is unavailable. Palm and palmar crease examination may provide complementary clinical information but are less accurate than conjunctival assessment.