Adult Influenza Patients Diagnosed by Multiplex Polymerase Chain Reaction Tests, but Not Rapid Antigen Tests, and Managed Successfully During the 2024 to 2025 Major Influenza-Endemic Season in a Tertiary Hospital in Japan.

We present the two adult cases of influenza diagnosed by multiplex polymerase chain reaction (PCR) in the 2024-2025 season, which was a major season of influenza in Japan. Although rapid antigen tests (RATs) were negative in these two cases, these patients were effectively treated by anti-influenza agents after influenza was definitively diagnosed by multiplex PCR. Relative low sensitivity and specificity might be shown in influenza diagnosis at bedside by RATs, therefore, these data suggest that multiplex PCR could be useful in influenza diagnosis and management during the influenza-endemic season.