A paper-based chromogenic strip and electrochemical sensor for semi-quantitative estimation of hemoglobin

Anemia and related blood disorders particularly prevalent among children and women in regions of sub-Saharan Africa and South Asia pose a major global health burden. Undiagnosed and untreated anemia often leads to severe health complications making accurate quantification of hemoglobin (Hb) critical for effective management. Conventional laboratory-based methods, though reliable, are often expensive, require expertise and are inaccessible in remote and rural areas, necessitating the need for affordable and easy-to-use diagnostic tools for estimation of hemoglobin. To address these challenges, a QR-code integrated, chromogenic paper-based strip and an electrochemical sensor for estimation of Hb has been developed. The developed chromogenic paper-based Hb-strip demonstrated estimation of Hb in the range of 4–16 g/dL and validated with standard spectrophotometric method. Semi-quantitative Hb estimation was achieved through RGB analysis. Characterization of the developed electrochemical sensor revealed a linear increase in anodic peak current with increasing hemoglobin concentration demonstrating strong correlation (R² = 0.97) and high sensitivity (5.932 μA/g·dL⁻¹), with detection and quantification limits of 0.31 and 1.03 g/dL, respectively. The QR-code embedded on the strip provided multilingual analytical information, enabling user-friendly interpretation. The developed chromogenic Hb-strips offers low-cost, point-of-care and scalable solution for estimation of Hb in low-resource healthcare settings.