Paper-Based Analytical Devices for Accurate Assessment of Transferrin Saturation in Diagnosed Clinical Samples from Ischemic Stroke Patients

For the first time,a paper-based analytical device (PAD) was developedfor the assessment of transferrin saturation (TSAT), which is definedas the ratio between iron bound to transferrin (Tf) and the totaliron-binding capacity (TIBC) of Tf. Both parameters were simultaneouslymeasured on the same PAD using ferrozine as a chromophore and a smartphoneas the color reader. To this end, Tf was first isolated from serumusing anti-Tf immunomagnetic beads to ensure that only the Tf-boundiron was measured, improving the selectivity and accuracy of TSATassessment. To demonstrate the practical utility of the device, itwas validated by analyzing a certified reference material, showingexcellent accuracy (E (r) < 4%) and goodprecision (RSD & LE; 6%). Finally, 18 diagnosed serum samples fromischemic stroke patients were analyzed by this approach, and the resultswere compared with those obtained by urea-PAGE, showing not only anexcellent correlation (r = 0.93, p < 0.05) but that the PAD approach has become statistically identicalto the free-interference urea-PAGE. In comparison with the slow, tedious,and non-miniaturized-PAGE, this PAD approach exhibited attractivecharacteristics such as low cost, disposability, and connectivity,showing great potential for future point-of-care testing,especially in developing countries and/or remote areas, where accessto medical or clinical facilities is limited.

Automated summary

For the first time, a paper-based analytica device (PAD) was developed to assess transferrin saturation (TSAT) using ferrozine as a chromophore and a smartphone as the color reader. The device measured both iron bound to transferrin (Tf) and total iron-binding capacity (TIBC) simultaneously, improving the accuracy and selectivity of TSAT assessment. The PAD approach exhibited attractive characteristics such as low cost and disposability, making it suitable for point-of-care testing in developing countries and remote areas.