A rapid diagnostic testing device for testing of a biological sample is provided. The device comprises a channeled construct, at least one lateral flow unit, and a cassette housing. The channeled construct is configured to receive a biological sample to form at least partially purified biological sample. The lateral flow unit is at least partially disposed in the cassette housing. The lateral flow unit comprises: a sample receiving zone, a conjugate zone and a detection zone. The sample receiving zone is operatively coupled to the channeled construct for receiving the partially purified biological sample comprising at least one analyte. The conjugate zone comprising a conjugate particle to bind the analyte is disposed adjacent to the first side of the sample receiving zone. The detection zone is disposed adjacent to the second side of the sample receiving zone and comprises at least one binding agent for detecting the analyte.