Self-testing for the detection of SARS-CoV-2 infection with rapid antigen tests for people with suspected COVID-19 in the community

Abstract

Objectives: To evaluate the performance of nasal mid-turbinate self-testing using rapid antigen detection tests (RDT) for persons with suspected coronavirus disease 2019 (COVID-19) in the community. Self-testing for COVID-19 infection with lateral flow assay severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RDT, provides rapid results and could enable frequent and extensive testing in the community, thereby improving the control of SARS-CoV-2.

Methods: Participants visiting a municipal SARS-CoV-2 testing centre, received self-testing kits containing either the BD Veritor System (BD-RDT) or Roche SARS-CoV-2 antigen detection test (Roche-RDT). Oro-nasopharyngeal swabs were collected from the participants for quantitative RT-PCR (qRT-PCR) testing. As a proxy for contagiousness, viral culture was performed on a selection of qRT-PCR positive samples to determine the Ct-value at which the chance of a positive culture dropped below 0.5 (Ct-value cut-off). Sensitivity and specificity of self-testing were compared to qRT-PCR with a Ct-value below the Ct value cut-off. Determinants independently associated with a false-negative self-test result were determined.

Results: A total of 3201 participants were included (BD-RDT n = 1595; Roche-RDT n = 1606). Sensitivity and specificity of self-testing compared with the qRT-PCR results with a Ct-value below the Ct-value cut-off were 78.4% (95% CI 73.2%-83.5%) and 99.4% (95% CI 99.1%-99.7%), respectively. A higher age was independently associated with a false-negative self-testing result with an odds ratio of 1.024 (95% CI 1.003-1.044).

Conclusions: Self-testing using currently available RDT has a high specificity and relatively high sensitivity to identify individuals with a high probability of contagiousness.

Keywords: Coronavirus disease 2019; Public health; Rapid antigen detection test; Self-testing; Severe acute respiratory syndrome coronavirus 2.

Fig. 1

Participant flow diagram. ∗Samples of participants were included in the analysis determining the Ct-value cut-off where the p for a positive viral culture was smaller than 0.5 but not in the analysis determining the sensitivity and specificity of self-testing.

Fig. 2

Ct-value distribution per quantitative RT-PCR platform for viral culture positive and viral culture negative samples and for rapid antigen detection test (RDT) positive and RDT negative samples.

figs1

Graphical depiction of the univariate logistic regression analysis performed to determine the Ct-value below which the chance (p) of having a positive viral culture was p = 0.5 (Ct-value cut-off) for the LDA qRT-PCR.

figs2

Graphical depiction of the univariate logistic regression analysis performed to determine the Ct-value below which the chance (p) of having a positive viral culture was p = 0.5 (Ct-value cut-off) for the AA qRT-PCR.