RESUMO
ObjectiveTo assess the diagnostic accuracy of three rapid antigen tests (Ag-RDTs) for detecting SARS-CoV-2 infection in the general population. DesignCross-sectional study with follow-up using pseudonymised record linkage. SettingThree Dutch public health service COVID-19 test sites. ParticipantsConsecutively included individuals aged 16 years and older presenting for SARS-CoV-2 testing. Main outcome measuresSensitivity, specificity, positive and negative predictive values of BD-Veritortm System (Becton Dickinson), PanBio (Abbott), and SD-Biosensor (Roche Diagnostics), applying routinely used sampling methods (combined oropharyngeal and nasal [OP-N] or nasopharyngeal [NP] swab), with molecular testing as reference standard. For SD-Biosensor, the diagnostic accuracy with OP-N sampling was also assessed. A viral load cut-off ([≥]5.2 log10 SARS-CoV-2 E-gene copies/mL) served as a proxy of infectiousness. ResultsSARS-CoV-2 prevalence and overall sensitivities with 95% confidence intervals were 188/1441 (13.0%) and 129/188 (68.6% [61.5%-75.2%]) for BD-Veritor, 173/2056 (8.4%) and 119/173 (68.8% [61.3%-75.6%]) for PanBio, and 215/1769 (12.2%) and 160/215 (74.4% [68.0%-80.1%]) for SD-Biosensor with routine sampling, and 164/1689 (9.7%) and 123/164 (75.0% [67.7%-81.4%]) for SD-Biosensor with OP-N sampling. In those symptomatic or asymptomatic at sampling, sensitivities were 72.2%-83.4% and 54.0%-55.9%, respectively. With a viral load cut-off, sensitivities were 125/146 (85.6% [78.9%-90.9%]) for BD-Veritor, 108/121 (89.3% [82.3%-94.2%]) for PanBio, 160/182 (87.9% [82.3%-92.3%]) for SD-Biosensor with routine sampling, and 118/141 (83.7% [76.5%-89.4%]) with OP-N sampling. Specificities were >99%, and positive and negative predictive values >95%, for all tests in most analyses. 61.3% of false negative Ag-RDT participants returned for testing within 14 days (median of 3 days, interquartile range 3) of whom 90.3% tested positive. ConclusionsThe overall sensitivities of the three Ag-RDTs were 68.6%-75.0%, increasing to at least 85.6% after the viral load cut-off was applied. For SD-Biosensor, the diagnostic accuracy with OP-N and NP sampling was comparable. Over 55% of false negative Ag-RDT participants tested positive during follow-up.
RESUMO
If a health care workers (HCW) experiences COVID-19 associated symptoms, SARS-CoV-2 testing must be performed as soon as possible, to prevent transmission of the virus and to guarantee continuity of care. The gold standard for the detection of SARS-CoV-2, RT-PCR, has a high sensitivity but usually takes 6-8 hours. Lateral flow antigen assays take only 15-30 minutes and do not need any high tech equipment. In a prospective study of our hospitals HCWs, we evaluated the sensitivity of the Panbio COVID-19 Ag Rapid Test (Abbott) against the molecular test Aptima SARS-CoV-2 Assay (Hologic) which uses Transcription Mediated Amplification (TMA). TMA positive samples were further subjected to a quantitative real-time SARS-CoV-2 PCR to obtain Ct values as an indication of the viral load. Of 1101 HCWs included in the study between November 2020 and February 2021, 84 (7.6%) were TMA positive, of which 48 (57.1%) were antigen test positive. Most false negative antigen test results occurred if the duration of symptoms had been [≤]1 day or [≥]7 days. Sensitivities for symptom onset of [≤]1, 2 or 3 days were 47.1%, 63.0% and 66.7% respectively. The Panbio rapid test is fast and easy to perform, but is not a suitable SARS-CoV-2 test to confirm or exclude COVID-19 in HCWs with a very recent onset of symptoms.
