The multiplex rtPCR was performed according to the manufacturer’s instruction (Seegene, Korea). The Anyplex™ II RV16 detection kit (Seegene, Korea) detects the following viruses: adenovirus, influenza A virus, influenza B virus, parainfluenza virus 1, parainfluenza virus 2, parainfluenza virus 3, parainfluenza virus 4, rhinovirus A/B/C, RSV A, RSV B, bocavirus 1/2/3/4, human metapneumovirus, coronavirus 229E, coronavirus NL63, coronavirus OC43, and enterovirus. Specimens that arrived before mid-morning from Monday to Friday were processed daily and results were provided by mid-afternoon. Specimens that arrived afterwards were processed on the following workday and reported by mid-afternoon. Dates of specimen collection and testing were available, but not date and time of reporting of results. For CRP, white blood cell count (WBC) and platelets, the most pathologic values within 3 days before and after rtPCR results were documented.