Accuracy of 2 Rapid Antigen Tests During 3 Phases of SARS-CoV-2 Variants

Abstract

IMPORTANCEVariants of SARS-CoV-2 have sequence variations in the viral genome that may alter the accuracy of rapid diagnostic tests. OBJECTIVE To assess the analytical and clinical accuracy of 2 rapid diagnostic tests for detecting SARS-CoV-2 during 3 phases of variants. DESIGN, SETTING, AND PARTICIPANTS This diagnostic study included participants aged 18 years or older who reported onset of COVID-19-like symptoms within the prior 5 days and were tested at multiple COVID-19 testing locations in King County, Washington, from February 17, 2021, to January 11, 2022, during 3 distinct phases of SARS-CoV-2 infection (pre-Delta, Delta, and Omicron). INTERVENTIONS Two anterior nasal swab specimens were collected from each participant-1 for onsite testing by the SCoV-2 Ag Detect Rapid Self-Test and 1 for reverse transcriptase-polymerase chain reaction (RT-PCR) testing. MAIN OUTCOMES AND MEASURES The analytical limit of detection of the 2 rapid diagnostic tests (SCoV-2 Ag Detect Rapid Self-Test and BinaxNOW COVID-19 Ag Card) was assessed using Omicron (B.1.1.529/BA.1), Delta (B.1.617.2), and a wild-type (USA-WA1/2020) variant. Diagnostic sensitivity and specificity of clinical testing for the rapid antigen tests were compared with that of RT-PCR testing. RESULTS A total of 802 participants were enrolled (mean [SD] age, 37.3 [13.3] years; 467 [58.2%]female), 424 (52.9%) of whom had not received COVID-19 vaccination and presented a median of 2 days (IQR, 1-3 days) from symptom onset. Overall, no significant differences were found in the analytical limit of detection or clinical diagnostic accuracy of rapid antigen testing across SARS-CoV-2 variants. The estimated limit of detection for both rapid nucleocapsid antigen tests was at or below a 50% tissue culture infectious dose of 62.5, and the positive percent agreement of the SCoV-2 Ag Detect Rapid Self-Test ranged from 81.2% (95% CI, 69.5%-89.9%) to 90.7% (95% CI, 77.9%-97.4%) across the 3 phases of variants. The diagnostic sensitivity increased for nasal swabs with a lower cycle threshold by RT-PCR, which correlates with a higher viral load. CONCLUSIONS AND RELEVANCEIn this diagnostic study, analytical and clinical performance data demonstrated accuracy of 2 rapid antigen tests among adults with COVID-19 symptoms across 3 phases of SARS-CoV-2 variants. The findings suggest that home-based rapid antigen testing programs may be an important intervention to reduce global SARS-CoV-2 transmission.

The Diagnostic Accuracy of SARS-CoV-2 Nasal Rapid Antigen Self-Test: A Systematic Review and Meta-Analysis

“…Of the 22 studies reviewed, 9 [ 11 , 12 , 13 , 14 , 18 , 25 , 35 , 37 , 39 ] used self-taken rapid antigen tests approved by the WHO for professional use [ 31 ], which are the STANDARD-Q COVID-19 Ag Test, Panbio COVID-19 Ag Rapid Test, LumiraDx SARS-CoV-2 Ag Test, Abbott Panbio COVID-19 Ag Rapid Test and SARS-CoV-2 Antigen Rapid Test (Flowflex).…”

“…When a test was performed in the first week of symptoms, the sensitivity increased significantly to 81%, whereas when it was performed during the second week, it decreased again to 54%. This meta-analysis also lags behind ours in terms of its publication date because four of the studies [ 14 , 25 , 35 , 38 ] we have included were published after its publication. Additionally, this meta-analysis, as with the previous one, examines the diagnostic accuracy of all types of rapid antigen tests in contrast with ours.…”

“…This difference may be due to any of the factors affecting sensitivity. This meta-analysis lags behind ours in terms of date, as it was published in August 2021 and 16 of the studies [ 11 , 12 , 14 , 15 , 16 , 18 , 19 , 20 , 21 , 23 , 25 , 33 , 34 , 35 , 37 , 38 ] we have included were published after the publication of the mentioned meta-analysis. Moreover, the meta-analysis by Brümmer et al concerns all types of rapid antigen tests (using nasal samples, nasopharyngeal samples and saliva samples) in contrast with ours, which calculates the diagnostic accuracy with nasal samples.…”

“…Furthermore, most of the studies mentioned in this meta-analysis [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 20 , 21 , 22 , 23 , 25 , 33 , 35 , 36 , 38 , 39 ] also used nasopharyngeal samples. Rapid antigen tests using nasopharyngeal samples are considered more reliable compared with nasal swab use due to the higher concentration of the virus [ 47 ].…”

Error in Byline

“…In the Original Investigation titled “Accuracy of 2 Rapid Antigen Tests During 3 Phases of SARS-CoV-2 Variants,” 1 published August 24, 2022, the academic degree shown in the byline for Dr Hau was changed from BA to PhD. This article has been corrected.…”