A short perspective on a COVID-19 clinical study: 'diagnosis of COVID-19 by RT-PCR using exhale breath condensate samples'.

Sawano, Makoto; Takeshita, Kyousuke; Ohno, Hideaki; Oka, Hideaki

Diagnosis of SARS-COV-2 infection (COVID-19) is currently based on detection of the viral RNA in nasopharyngeal swab samples by reverse transcription polymerase chain reaction (RT-PCR). However, sampling via nasopharyngeal swabs frequently provokes sneezing or coughing, which results in increased risk of the viral dissemination and environmental contamination. Furthermore, the sensitivity associated with the PCR tests s limited to 60%-70%, which is mainly attributable to technical deficiency in sampling. Given that the disease is transmitted via exhaled aerosol and droplets, and that the exhaled breath condensate (EBC) is the established modality for sampling exhaled aerosol, detection of the viral RNA in EBC is a promising approach for safe and efficient diagnosis of the disease. Subjects are those patients who are diagnosed with COVID-19 by positive nasopharyngeal swab PCR test and admitted to Saitama Medical Center, Japan. EBC samples will be collected using an R-tube® or R-tubeVent® device. Collected EBC samples will be introduced into a nucleic acid purifier. The purified nucleic acids will undergo amplification through RT-PCR for detection and quantification of SARS-COV-2 RNA. To date we have collected eight samples from seven subjects. Among them, two samples from two subjects tested positive for SARS-COV-2 RNA by the RT-PCR. Reflecting the second wave of COVID-19 prevalence in Japan, new admissions of COVID-19 patients to the Saitama Medical Center are increasing, and we are expecting to collect at least 50 EBC samples from 25 patients before the end of this year.