JAMA Netw Open

Do throat swabs improve diagnostic accuracy of COVID-19 rapid tests?

December 7, 2023

In this multicenter randomized clinical trial, investigators compared the diagnostic accuracy of self- and healthcare worker (HCW)-collected nasal vs. throat swab specimens for COVID-19 rapid antigen testing. Researchers 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, self-collected nasal specimens had a higher sensitivity than throat specimens for symptomatic participants.

• 2,491 participants were randomized to self-collected or HCW-collected nasal and throat swab specimens for rapid antigen testing. Additional nasal and throat swab specimens for RT-PCR were also collected and tested as the reference standard.
• 2,674 (90.9%) had complete test results and were included in the final analysis (1,535 [57.4%] women; median age, 40 years); 1,074 (40.2%) had COVID-19 symptoms, and 827 (30.9%) were positive for SARS-CoV-2 by RT-PCR.
• HCW-collected throat specimens had higher mean sensitivity than HCW-collected nasal specimens for rapid antigen testing (69.4% [95% confidence interval (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).
• Authors conclude that 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.

Source:

Todsen T, et al. (2023, December 1). JAMA Netw Open. COVID-19 Rapid Antigen Tests With Self-Collected vs Health Care Worker-Collected Nasal and Throat Swab Specimens: A Randomized Clinical Trial. https://pubmed.ncbi.nlm.nih.gov/38055280/