A lateral flow assay detects and differentiates between viral and bacterial infections. A combined point of care diagnostic device tests markers for viral infection and markers for bacterial infection, to effectively assist in the rapid differentiation of viral and bacterial infections. In one preferred embodiment, the bacterial marker is CRP. In another preferred embodiment, the viral marker is MxA. In some embodiments, it is unnecessary to lyse the cells in the sample prior to applying it to the device.