An eight hour fast, a pin prick, and a blood test. Standard procedure when testing for diabetes, but could the same diagnosis be made by wearing an epidermal patch instead? Researchers at Northwestern University are working towards making that a reality with their “lab on the skin” device which collects, stores, and analyzes sweat in real time (1). Why focus on sweat? John Rogers, Professor of Materials Science and Engineering at Northwestern University, explains, “Sweat is an interesting class of biofluid because it can be captured noninvasively. We were looking to work on a simple type of device capable of performing in situ chemical analysis of sweat, as well as analyzing sweat rates and total sweat loss.” Sweat contains an array of biomarkers, so the approach has potential as an alternative to invasive diagnostic tests.