Contrary to the classical methods (Immunofluorescence and ELISA) which are laborious and time consuming, Check4® RSV (QBX020RSV) is a fast, simple and highly sensitive test for the rapid and reliable detection of RSV in the respiratory tract. The method employs a unique combination of monoclonal dye conjugate and polyclonal solid phase antibodies to selectively identify RSV with a high degree of sensitivity and specificity. After collection and treatment, the sample is added to the sample well (A) of the reaction device. As the test sample flows through the absorbent device, the labelled antibody-dye conjugate binds to the RSV antigen (when present in the sample) forming an antibody antigen complex. This complex binds to the polyclonal antibody in the positive reaction window producing a rose-pink coloured band (B). In the absence of RSV, there is no line in the positive reaction zone. The reaction mixture continues flowing through the absorbent device, past the positive reaction zone and control zone. Unbound conjugate binds to the reagent in the control window (C) producing a rose-pink coloured band demonstrating that the reagents are functioning correctly.