Reverse transcriptase polymerase chain reaction (RT-PCR) assays for coronavirus disease 2019 (COVID-19) should be interpreted with clinical, epidemiological history and exposure risk to avoid misdiagnosis. We report a cruise-ship worker with significant travelling history, presented with acute respiratory symptoms and radiographic evidence of viral pneumonia. Initial RNA-dependent RNA polymerase (RdRp) gene confirmatory assay was negative. Use of a more robust RT-PCR assay detected ORF1ab, N and S genes for COVID-19, and the diagnosis was supported by an IgM and IgG positive COVID-19 serology. Subsequent follow up samples which reported inconsistencies in detecting RdRp gene also raise the concern of reliability of RdRp gene as the confirmatory assay for diagnosis of COVID-19. Patient later had prolonged viral shedding beyond serological recovery, with a negative viral culture reflecting non-infectivity.
SARS-CoV-2 ; COVID-19 ; Reverse Transcriptase Polymerase Chain Reaction ;