METHODS: For a hypothetical one million patients, a budget impact model was developed to assess the difference in total healthcare costs and per patient per year (PPPY) costs before and after adding a rapid PCR test to detect influenza and RSV. The model evaluated testing fees (rapid PCR test, cFDA-PCR test, rapid antigen detection tests, immunochromatographic assay), hospitalization costs, influenza and RSV medication and supportive care costs, costs for other laboratory tests, labor costs of doctors, laboratory technicians and nurses, and other hospital operating costs for one year. Costs were estimated in 2022 Chinese yuan. The prevalence of influenza and RSV, length of influenza and RSV disease, percentage of RSV hospitalization, percentage of other laboratory tests during RSV hospitalization, and RSV hospitalization duration were obtained from published sources or expert opinions. In the base case, the market share of the rapid PCR test was assumed to be 60%, according to market research.