Diagnostic assay devices for detecting the presence of an analyte in a sample solution may comprise a microreactor configured to form a sample solution containing the analyte, flow the sample solution therethrough in a first direction to form an analyte-capture molecule complex, and transfer the sample solution to an absorbent strip pad configured to flow therethrough, in a second direction crossing the first direction, the sample solution including the analyte-capture molecule complex and indicate a presence of the analyte-capture molecule complex. The diagnostic devices may be used, for example, to identify the presence of SARS-Cov2, RSV, influenza A, influenza B or other pathogens in samples from patients.