A Case of COVID-19 Failed in Viral Identification but Showed Consistent Host Responses to Severe Acute Respiratory Syndrome Coronavirus 2

In a 75-year-old hemodialysis patient, pneumonia manifested with computed tomography (CT) images suggestive of coronavirus disease 2019 (COVID-19). Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ribonucleic acid (RNA) was not detected with repeated polymerase chain reaction (PCR) tests, but serum immunoglobulin G (IgG) and IgM antibodies against SARS-CoV-2 turned positive with two different assay kits. The patient was thus treated as a probable COVID-19 case, and then recovered through the intensive care including ciclesonide, favipiravir, and methyl prednisolone. In PCR-negative cases, the diagnosis of COVID-19 cannot be established at present, but such COVID-19 cases certainly exist. To avoid a delay in treatment of COVID-19, available diagnostic tools should be utilized with careful attention for their limitations.