Evaluating the clinical utility and sensitivity of SARS-CoV-2 antigen testing in relation to RT-PCR Ct values
- PDF / 386,215 Bytes
- 3 Pages / 595.276 x 790.866 pts Page_size
- 88 Downloads / 154 Views
CORRESPONDENCE
Evaluating the clinical utility and sensitivity of SARS‑CoV‑2 antigen testing in relation to RT‑PCR Ct values Lukas Lanser1 · Rosa Bellmann‑Weiler1 · Karla‑Wanda Öttl1 · Lukas Huber1 · Andrea Griesmacher2 · Igor Theurl1 · Günter Weiss1 Received: 4 October 2020 / Accepted: 21 October 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
To the Editor, Diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in patients with suspected coronavirus disease 2019 (COVID-19) is most widely performed with real time polymerase chain reaction (RT-PCR) considered as gold standard [1]. RT-PCR is a highly sensitive diagnostic method for detecting viral ribonucleic acid (RNA) with the disadvantages of logistics for transport of samples to specific laboratories and the relative long duration of the diagnostic method. Positive SARS-CoV-2 RT-PCR also do not allow definitive conclusions whether the subject is still contagious or not. This can be partly attained by establishing the cycle threshold (Ct) value depicting the particular amount of viral RNA in the sample and thus allowing a conclusion on the viral load and infectivity [2]. However, because of the diagnostic effort and duration of the test, faster and less laborious tests attract interest which may help to rapidly identify and contain infected individuals. Therefore, point-of-care-testing with antigen tests, providing results in a couple of minutes, is currently evaluated for routine clinical use. We compared the SARS-CoV-2 antigen detection in nasopharyngeal swab samples by the Panbio™ COVID-19 Ag Rapid test (Abbott, Chicago, Illionis) with the simultaneous routinely conducted RT-PCR analysis of SARS-CoV-2 orf1 RNA detection with the c obas® analyzer (Roche Diagnostics GmbH, Mannheim, Germany). The nasopharyngeal swab samples were collected from 53 patients with PCRconfirmed SARS-CoV-2 infection during their hospital stay in different stages of the disease. Panbio™ COVID-19 Ag * Günter Weiss guenter.weiss@i‑med.ac.at 1
Department of Internal Medicine II, Innsbruck Medical University, Anichstraße 35, 6020 Innsbruck, Austria
Central Institute for Medical and Chemical Laboratory Diagnosis, Innsbruck University Hospital, Innsbruck, Austria
2
Rapid test was performed right after nasopharyngeal swab sampling while RT-PCR was routinely performed in our central laboratory facility. RT-PCR was negative in two patients suggesting an already subsided infection; consistent with it the Panbio™ COVID-19 Ag Rapid test was also negative. Among 51 RT-PCR SARS-CoV-2 positive patients, the Panbio™ COVID-19 Ag Rapid test was positive in 31 subjects depicting a poor sensitivity of 60.8% (95% CI 46.1–74.2%), compared to 93.3% in the manufacturer’s information. In the 14 patients with a Ct-value ≤ 25, being indicative for higher viral loads, the sensitivity for the Panbio™ COVID-19 Ag Rapid test was at a level of 85.7% (95% CI 57.2–98.2%, Table 1). Panbio™ COVID-19 Ag Rapid test was positive in 36.4% (95% CI 17.2–59.3%) of the patients w
Data Loading...
