The patient was a 56-year-old man who presented with a 14-day history of fever, and had been diagnosed by a physician as having pneumonia on the basis of the findings of chest CT. He had not travelled abroad and gave no history of close contact with any patients with suspected or confirmed COVID-19. His chest CT showed bilateral multiple ground-glass opacities, distributed predominantly in the peripheral lung regions. We suspected COVID-19 pneumonia based on the chest CT findings. A nasopharyngeal swab PCR test (PCR) for SARS-CoV-2 on day 1 returned a negative result. The following day, a nasopharyngeal swab and a sputum specimen were submitted for repeat PCR testing, and both yielded positive results, confirming the diagnosis of COVID-19 pneumonia in the patient.