Sweat-Based in Vitro Diagnostics (IVD): From Sample Collection to Point-of-Care Testing (POCT)

Sweat-based diagnostics offer an exciting avenue to noninvasively monitor analytes which had previously only been available through painful blood draws. Sweat is enriched with physiologically valuable information, and recent proteomic studies have identified numerous critical analytes which have highly correlated levels in blood, interstitial fluid and sweat. However, usage of sweat for health monitoring has not been studied extensively due to the substantial challenge of assembling a composite clinic-ready device. Recent advances in soft electronics have made this goal realizable, as these devices can perform electronic or optical monitoring on a flexible substrate using small volumes of liquid. While this field is still in its infancy, this review examines the physiological composition of sweat, various improvements in material science that improve sensor design, existing FDA approvals, methods of extracting sweat and comparisons to blood-based tests. Furthermore, this review assesses the critical challenges which must be overcome for this type of technology to make it out of research laboratories and into continuous clinical use. We believe that once properly harnessed, sweat-based diagnostics can provide patients a painless monitoring tool which can be customized to track a wide variety of medical conditions from the comfort of a patient's own home.