Abstract
Background: The diagnostic accuracy of unsupervised self-testing with rapid antigen diagnostic tests (Ag-RDTs) is mostly unknown. We studied the diagnostic accuracy of a self-performed SARS-CoV-2 saliva and nasal Ag-RDT in the general population.
Methods: This large cross-sectional study consecutively included unselected individuals aged ≥ 16 years presenting for SARS-CoV-2 testing at three public health service test sites. Participants underwent molecular test sampling and received two self-tests (the Hangzhou AllTest Biotech saliva self-test and the SD Biosensor nasal self-test by Roche Diagnostics) to perform themselves at home. Diagnostic accuracy of both self-tests was assessed with molecular testing as reference.
Results: Out of 2819 participants, 6.5% had a positive molecular test. Overall sensitivities were 46.7% (39.3-54.2%) for the saliva Ag-RDT and 68.9% (61.6-75.6%) for the nasal Ag-RDT. With a viral load cut-off (≥ 5.2 log10 SARS-CoV-2 E-gene copies/mL) as a proxy of infectiousness, these sensitivities increased to 54.9% (46.4-63.3%) and 83.9% (76.9-89.5%), respectively. For the nasal Ag-RDT, sensitivities were 78.5% (71.1-84.8%) and 22.6% (9.6-41.1%) in those symptomatic and asymptomatic at the time of sampling, which increased to 90.4% (83.8-94.9%) and 38.9% (17.3-64.3%) after applying the viral load cut-off. In those with and without prior SARS-CoV-2 infection, sensitivities were 36.8% (16.3-61.6%) and 72.7% (65.1-79.4%). Specificities were > 99% and > 99%, positive predictive values > 70% and > 90%, and negative predictive values > 95% and > 95%, for the saliva and nasal Ag-RDT, respectively, in most analyses. Most participants considered the self-performing and result interpretation (very) easy for both self-tests.
Conclusions: The Hangzhou AllTest Biotech saliva self Ag-RDT is not reliable for SARS-CoV-2 detection, overall, and in all studied subgroups. The SD Biosensor nasal self Ag-RDT had high sensitivity in individuals with symptoms and in those without prior SARS-CoV-2 infection but low sensitivity in asymptomatic individuals and those with a prior SARS-CoV-2 infection which warrants further investigation.
Keywords: Antigen test; COVID-19; Cross-sectional Study; Diagnostic test accuracy; Nasal test; Rapid antigen detection test; SARS-CoV-2; Saliva test.
【저자키워드】 COVID-19, SARS-CoV-2, cross-sectional study, antigen test, rapid antigen detection test, Diagnostic test accuracy, Saliva test., Nasal test, 【초록키워드】 public health, Saliva, cross-sectional, SARS-COV-2 infection, diagnostic test, diagnostic, nasal, Symptom, Antigen, SARS-CoV-2 detection, sensitivity, Diagnostic accuracy, Positive predictive value, Accuracy, SARS-CoV-2 testing, Viral load, Interpretation, Rapid, General population, molecular, antigen detection, Ag-RDT, E-gene, Negative predictive value, Participants, subgroups, individual, Ag-RDTs, participant, cut-off, positive, Roche Diagnostics, molecular test, SD Biosensor, MOST, asymptomatic individual, presenting, analyses, symptomatic and asymptomatic, 【제목키워드】 Saliva, cross-sectional, nasal, Antigen, Accuracy,