Article: Srinivasan, B; O’Dell, D; Finkelstein, JL; Lee, S; Erickson, D; Mehta, S; “ironPhone: Mobile Device-Coupled Point-of-Care Diagnostics for Assessment of Iron Status by Quantification of Serum Ferritin”, Biosensors & Bioelectronics, 99:115-121
Abstract: Iron deficiency (ID) is an urgent public health problem that has devastating effects on maternal and child health. However, due to poor access and affordability, screening and diagnosis for ID is often limited to proxy hemoglobin measurements alone. Here, we report the development and validation of ironPhone, a mobile device coupled portable diagnostics for quantification of serum ferritin concentrations, an iron status biomarker, within a few minutes, from a drop of fingerprick blood. The ironPhone diagnostic platform comprises of a smartphone accessory, an app, and a disposable lateral flow immunoassay test strip to quantify serum ferritin. For initial validation in the lab, we optimized and evaluated the performance of ironPhone with known ferritin concentrations in spiked buffer and serum samples. Following lab validation, we performed a human validation by collecting fingerprick whole blood samples from 20 participants to assess iron status using ironPhone and compared the results with the laboratory standard IMMULITE 2000 analyzer. Findings from the ironPhone for the buffer and spiked serum samples provided a calibration curve with R-2 values of 0.97 (n=27) and 0.93 (n=12), respectively. On comparison with the laboratory standard IMMULITE analyzer in whole blood samples, a correlation of 0.92 (P < 0.0001) was observed with a sensitivity of over 90% for predicting ID (ferritin < 15.0 mu g/L) via the ironPhone, demonstrating its promise for iron status assessment at the point-of-care.
Funding Acknowledgement: National Science Foundation [IIP-1430092]; Nutrition International [10-8007-CORNE-01]; Thrasher Research Fund Early Career Award
Funding Text: S.M. and D.E. acknowledge funding from the National Science Foundation (grant IIP-1430092), and Nutrition International, formerly Micronutrient Initiative (project# 10-8007-CORNE-01). B.S. was also supported by a Thrasher Research Fund Early Career Award. The authors also thank Erica Bender for performing fingerpricks and venepuncture sample collection in the human study, and Vicky Simon for conducting the validation assays using IMMULITE system and ELISA kits in the Human Metabolic Research Unit in the Division of Nutritional Sciences.