A rapid point-of-care test for vancomycin monitoring at the clinical bedside

Vancomycin requires individualized dosing guided by therapeutic drug monitoring, but current laboratory assays are slow and centralized. We describe a competition-format microarray assay on a poly(oligo(ethylene glycol) methacrylate-co-glycidyl methacrylate) brush integrated into a single-use microfluidic cassette and portable reader to quantify vancomycin directly from fingerstick volumes of whole blood in 30 min. The assay shows a limit of detection of 0.8 μg/mL and precise quantification across the clinical range, with relative error below 20%. In a pilot study of 31 patient samples, cassette measurements correlated strongly with routine hospital testing with minimal bias, including when operated by minimally trained coordinators. This work establishes an approach for rapid, decentralized vancomycin monitoring that could support area-under-the-curve-based dosing in settings where access to high-complexity laboratories is limited and suggests a path toward extending therapeutic drug monitoring to point-of-care devices.