Microfluidic devices for determining whether an analyte is present in a sample are provided. The microfluidic devices include a polymeric medium that includes a first analyte detection domain having a first covalently bound capture member that specifically binds to a first analyte, and a second analyte detection domain having a second covalently bound capture member that specifically binds to a second analyte. Also provided are methods of using the subject microfluidic device, systems and kits that use the subject microfluidic devices, as well as methods of producing the same.