Background: RT-PCR on nasopharyngeal (NPS)/oropharyngeal swabs is the gold standard for diagnosis of SARS-CoV-2 infection and viral load monitoring. Oral fluid (OF) is an alternate clinical sample, easy and safer to collect and could be useful for COVID-19 diagnosis, monitoring viral load and shedding. Methods: Optimal assay conditions and analytical sensitivity were established for the commercial Simplexa™ COVID-19 Direct assay adapted to OF matrix. The assay was used to test 337 OF and NPS specimens collected in parallel from 164 hospitalized patients; 50 bronchoalveolar lavage (BAL) specimens from a subgroup of severe COVID-19 cases were also analysed. Results: Using Simplexa™ COVID-19 Direct on OF matrix, 100% analytical detection down to 1 TCID50/mL (corresponding to 4 × 10 3 copies (cp)/mL) was observed. No crossreaction with other viruses transmitted through the respiratory toute was observed. Parallel testing of 337 OF and NPS samples showed highly concordant results (κ = 0.831; 95 % CI = 0.771–0.891), and high correlation of Ct values (r = 0.921; p < 0.0001). High concordance and elevated correlation was observed also between OF and BAL. Prolonged viral RNA shedding was observed up to 100 days from symptoms onset (DSO), with 32% and 29% positivity observed in OF and NPS samples, respectively, collected between 60 and 100 DSO. Conclusions: Simplexa™ COVID-19 Direct assays on OF have high sensitivity and specificity to detect SARS-CoV-2 RNA and provide an alternative to NPS for diagnosis and monitoring SARS-CoV-2 shedding.
【저자키워드】 real time RT-PCR, SARS-CoV-2 RNA, oral fluid, direct assay, 【초록키워드】 COVID-19, SARS-CoV-2, Hospitalized, severe COVID-19, Infection, RT-PCR, BAL, Concordance, Sensitivity and specificity, Viral load, nasopharyngeal, COVID-19 diagnosis, oral, Swab, correlation, analytical sensitivity, Bronchoalveolar lavage, Prolonged, Viral RNA shedding, gold standard, high correlation, specimen, symptoms onset, NPs, Direct, 95 % CI, was used, detect, collected, virus, transmitted, elevated, analysed, condition, diagnosis and monitoring, diagnosis of SARS-CoV-2, 【제목키워드】 SARS-CoV-2, Duration, Rapid, shedding, oral, Sample,