Diagnostic Performance of SARS-CoV-2 Rapid Antigen Test in a Large, German Cohort

Abstract

We assessed the performance of a rapid antigen test (RAT) in everyday clinical practice. Between 1 November 2020 until 1 April 2021 all in-patients at the Helios University Hospital Wuppertal, Germany, as well as the accompanying relatives at the Children’s Hospital received a SARS-CoV-2 RAT and a SARS-CoV-2 RT-PCR prior to admission. Out of 3686 patients, 22 (0.6%) subjects were tested positive by RT-PCR and RAT, and 3591 (97.4%) were negative by both methods, showing discordant results: RT-PCR+/RAT− in 58 (1.6%) and RT-PCR−/RAT+ in 15 patients (0.4%). Overall sensitivity and specificity of RAT was 27.5% (95%CI 18.1–38.6%) and 99.6% (95%CI 99.3–99.8%), respectively. The sensitivity was slightly higher in adults (30.4%, 95%CI 18.8–90.9%) than in pediatric subjects (20.8%, 95%CI 7.1–42.2%). False negative RAT had a statistically higher Ct-value (p < 0.001) compared to true positive values, and overall sensitivity increased to 80% [59.3–93.2%] with Ct value < 30. While the sensitivity of the RAT was poor compared with the RT-PCR, the specificity was excellent. However, the sensitivity increased with lower Ct value, and with the right anamnesis the RAT can be a quick and easy approach to distinguish people who are infectious with SARS-CoV-2 from noninfectious people, enabling appropriate triage in clinical practice while waiting for the RT-PCR result.

Performance Evaluation of the STANDARDTM Q COVID-19 and PanbioTM COVID-19 Antigen Tests in Detecting SARS-CoV-2 during High Transmission Period in Mozambique

“…The relatively low sensitivity observed in our study for both Ag-RDTs could be attributed to several factors, including deficient specimen collection [ 10 ], test performance, and patients’ clinical characteristics, including their viral loads [ 16 ]. Our study also observed a lower sensitivity (<35%) in asymptomatic cases, similar to those observed in other reports [ 22 , 24 ], that are probably associated with lower viral loads in those patients [ 4 , 20 ]. Evaluations in Europe and America observed a higher sensitivity of Ag-RDTs when compared to studies in Asia and Africa.…”

“…Additionally, the results obtained from Cohen’s kappa coefficient analysis showed better agreement in symptomatic patients, with symptoms 1 to 5 days before the test, thus reinforcing better applicability of both RDTs in this group of patients [ 21 ]. Another study, performed by Mboma et al (2021), found an overall sensitivity of 30.4% (95%CI: 18.8–90.9%) in adults attending a hospital being higher at 52.9% in symptomatic cases [ 22 ]. Furthermore, Jegerlehner et al (2021), in a different study, found an overall sensitivity of 65.3% (95% CI: 56.8–73.1) and 44.4% (95% CI 24.4–65.1) in asymptomatic cases [ 23 ].…”

Rapid Antigen Test for SARS-CoV-2: Results of Validation and Use in Real Life

“…The specificity was excellent. With the right cut-off the RAT can be useful to distinguish SARS-CoV-2-infected subjects who can transmit the infection from noninfectious people, enabling appropriate triage while waiting for the RT-PCR result [ 17 ].…”

Large-scale implementation of rapid antigen testing system for COVID-19 in workplaces

“…While some asymptomatic screening programs have been described in the literature ( 12 – 15 ), they have been limited in size and scope or have been focused on contextually different settings outside of workplaces ( 16 ) , including clinical settings ( 17 ). Furthermore, other large-scale screening programs that have a serial design (i.e., regular, frequent screening rather than ad hoc or one-time testing) have not had their implementation process systematically described, data collected, nor even suggestive evidence of their efficacy.…”

“…Without asymptomatic testing, there are no other ways to detect these infectious individuals until they become symptomatic, after which spread could have already occurred, and the ability to test-trace-isolate is substantially hindered (6,7). The larger consequence of this information gap is that these infectious cases contribute to spread, uncontrolled transmission, and workplace shutdowns (5,(10)(11)(12)(13). Rapid antigen screening for COVID-19 provides useful information on who is likely to be infectious (11), and information can be gained in real time to proactively manage infectious individuals, particularly when serial screening (e.g., at least two times weekly) is one of several layers of protection alongside others such as vaccination, masking, physical distancing, and ventilation (1).…”