Provided herein are flexible, microfluidic epidermal systems and methods useful in the analysis of biofluids for biomarkers corresponding to a variety of conditions and methods of use. The provided systems configured to create conformal contact with the skin to allow for medical testing or screening, either in situ or later external laboratory testing. The described devices and methods may be used for cystic fibrosis screening, glucose monitoring, drug and/or alcohol testing, creatinine monitoring, urea monitoring, pH measurement and dialysis treatment efficacy testing.
