Smartphone-Enabled Paper-Based Hemoglobin Sensor for Extreme Point-of-Care Diagnostics

We report a simple, affordable (?0.02 US $/test), rapid (within 5 min), and quantitative paper-based sensor integrated with smartphone application for on-spot detection of hemoglobin (Hgb) concentration using approximately 10 ?L finger-pricked blood. Quantitative analytical colorimetry is achieved via an Android-based (Sens-Hb), integrating key operational steps image acquisition, real-time analysis, result dissemination. Further, feedback from the machine learning algorithm adaptation calibration data offers consistent dynamic improvement precise predictions test results. Our study reveals successful deployment extreme point-of-care in rural settings where no infrastructural facilities diagnostics are available. The Hgb device validated both controlled laboratory environment (n = 200) on field experiments 142) executed four different Indian villages. Validation results well correlated pathological gold standard (r 0.9583) high sensitivity specificity healthy 136) (>11 g/dL) (specificity: 97.2%), mildly anemic 55) (<11 (sensitivity: 87.5%, specificity: 100%), severely 9) (<7 100%, 100%) samples. Results trials reveal that only below 5% cases interpreted erroneously by classifying patients as ones. On-field has unveiled kit to be extremely user friendly can handled minimally trained frontline workers catering needs underserved communities.