COVID-19 Rapid Antigen Tests With Self-Collected vs Health Care Worker–Collected Nasal and Throat Swab Specimens

Abstract

ImportanceSelf- or health care worker (HCW)–collected nasal swab specimens are the preferred sampling method to perform rapid antigen testing for COVID-19, but it is debated whether throat specimens can improve test sensitivity.ObjectiveTo compare the diagnostic accuracy of self- and HCW-collected nasal vs throat swab specimens for COVID-19 rapid antigen testing.Design, Setting, and ParticipantsThis per-protocol multicenter randomized clinical trial was conducted from February 15 through March 25, 2022. The participants, individuals aged 16 years or older requesting a COVID-19 test for diagnostic or screening purposes, had 4 specimens collected for individual testing at 1 of 2 urban COVID-19 outpatient test centers in Copenhagen, Denmark.InterventionsParticipants were randomized 1:1 to self-collected or HCW-collected nasal and throat swab specimens for rapid antigen testing. Additional HCW-collected nasal and throat swab specimens for reverse transcriptase–polymerase chain reaction (RT-PCR) were used as the reference standard.Main Outcomes and MeasuresThe primary outcome was sensitivity to diagnose COVID-19 of a self- vs HCW-collected nasal and throat specimen for rapid antigen testing compared with RT-PCR.ResultsOf 2941 participants enrolled, 2674 (90.9%) had complete test results and were included in the final analysis (1535 [57.4%] women; median age, 40 years [IQR, 28-55 years]); 1074 (40.2%) had COVID-19 symptoms, and 827 (30.9%) were positive for SARS-CoV-2 by RT-PCR. Health care worker–collected throat specimens had higher mean sensitivity than HCW-collected nasal specimens for rapid antigen testing (69.4% [95% CI, 65.1%-73.6%] vs 60.0% [95% CI, 55.4%-64.5%]). However, a subgroup analysis of symptomatic participants found that self-collected nasal specimens were more sensitive than self-collected throat specimens for rapid antigen testing (mean sensitivity, 71.5% [95% CI, 65.3%-77.6%] vs 58.0% [95% CI, 51.2%-64.7%]; P < .001). Combining nasal and throat specimens increased sensitivity for HCW- and self-collected specimens by 21.4 and 15.5 percentage points, respectively, compared with a single nasal specimen (both P < .001).Conclusions and RelevanceThis randomized clinical trial found that a single HCW-collected throat specimen had higher sensitivity for rapid antigen testing for SARS-CoV-2 than a nasal specimen. In contrast, the self-collected nasal specimens had higher sensitivity than throat specimens for symptomatic participants. Adding a throat specimen to the standard practice of collecting a single nasal specimen could improve sensitivity for rapid antigen testing in health care and home-based settings.Trial RegistrationClinicalTrials.gov Identifier: NCT05209178

Impact of Swabbing Location, Self-Swabbing, and Food Intake on SARS-CoV-2 RNA Detection

“…Furthermore, self-collected nasal swabs for SARS-CoV-2 are easy to perform, and are highly accepted [ 8 , 24 , 25 ]. Interestingly, the sensitivity of the nasal swabs was slightly higher in the present study compared to previously published studies, stating a sensitivity of approximately 85% for professionally collected or self-collected nasal swabs [ 4 , 26 , 27 , 28 ]. This observed difference may be related to the sensitive quantitative testing method used in the present study compared to semi-quantitative techniques or rapid antigen testing used in previous studies [ 4 , 27 , 29 , 30 ].…”

“…Interestingly, the sensitivity of the nasal swabs was slightly higher in the present study compared to previously published studies, stating a sensitivity of approximately 85% for professionally collected or self-collected nasal swabs [ 4 , 26 , 27 , 28 ]. This observed difference may be related to the sensitive quantitative testing method used in the present study compared to semi-quantitative techniques or rapid antigen testing used in previous studies [ 4 , 27 , 29 , 30 ]. Although it has been shown that semi-quantitative techniques correlate qualitatively and quantitatively, the sensitivity of the QNAT used in the present study might be slightly higher [ 17 ].…”

Molecular Detection of SARS-CoV-2 From Throat Swabs Performed With or Without Specimen Collection From the Tonsils: Protocol for a Multicenter Randomized Controlled Trial

“…Some studies perform a throat swab by only collecting specimens from the posterior oropharyngeal wall [ 12 , 13 ], while others also include a swab of the palatine tonsils for SARS-CoV-2 testing [ 14 , 15 ]. However, recent studies suggest that throat swabs, including the palatine tonsils, have a higher sensitivity for SARS-CoV-2 detection than nasal and nasopharyngeal swabs in asymptomatic and early infectious stages [ 16 , 17 ]. SARS-CoV-2 primarily uses the tissue-specific proteases TMPRSS2, TMPRSS4, and TMPRSS11D as cellular entry factors via angiotensin-converting enzyme 2 channels, which are richly expressed in the tonsil crypts [ 18 , 19 ].…”