A method is provided for reverse transcription-polymerase chain reaction (RT-PCR) accomplished by: a) amplifying a reverse transcribed cDNA in a mixture containing Norovirus Genogroup I and Norovirus Genogroup II primers and probes, in which the Norovirus primers and probes can distinguish between Genogroup I and Genogroup II viruses; b) quantifying virus; and c) normalizing data based on a universal internal RNA control. Optionally, the method may also include primers and probes for Enteroviruses. The present invention also provides a reaction mixture containing Norovirus Genogroup I and Norovirus Genogroup II primers and probes, in which the Norovirus primers and probes can distinguish between Genogroup I and Genogroup II viruses and universal internal RNA control primers and probes.