• FluTrackers.com Inc. does not provide medical advice. Information on this web site is collected from various internet resources, and the FluTrackers board of directors makes no warranty to the safety, efficacy, correctness or completeness of the information posted on this site by any author or poster. The information collated here is for instructional and/or discussion purposes only and is NOT intended to diagnose or treat any disease, illness, or other medical condition. Every individual reader or poster should seek advice from their personal physician/healthcare practitioner before considering or using any interventions that are discussed on this website. By continuing to access this website you agree to consult your personal physican before using any interventions posted on this website, and you agree to hold harmless FluTrackers.com Inc., the board of directors, the members, and all authors and posters for any effects from use of any medication, supplement, vitamin or other substance, device, intervention, etc. mentioned in posts on this website, or other internet venues referenced in posts on this website.
  • We are not asking for any donations. Do not donate to any entity who says they are raising funds for us.

Am J Emerg Med . Comparison of rapid nucleic acid amplification tests and rapid antigen tests for influenza in the emergency department

tetano

Editor, Senior Moderator
Am J Emerg Med


. 2025 Sep 12:99:25-30.
doi: 10.1016/j.ajem.2025.09.022. Online ahead of print. Comparison of rapid nucleic acid amplification tests and rapid antigen tests for influenza in the emergency department

Sukyo Lee[SUP] 1 [/SUP], Jong-Hak Park[SUP] 1 [/SUP], Hanjin Cho[SUP] 1 [/SUP], Sungwoo Moon[SUP] 1 [/SUP], Sejoong Ahn[SUP] 2 [/SUP]



Affiliations
Abstract

Background: Influenza is a seasonal epidemic that poses significant health risks. Early antiviral treatment is recommended, making rapid and accurate diagnostic testing essential. Although rapid antigen tests (RATs) are widely used, they have limited sensitivity. In contrast, rapid nucleic acid amplification tests (NAATs) may offer improved diagnostic accuracy. This study compares the performance of a rapid NAAT and RAT for influenza in the emergency department.
Methods: This prospective comparative study evaluated the rapid NAAT (ID NOW Influenza A&B, Abbott) and the RAT (BD Veritor System for Rapid Detection of Flu A + B, BD). Paired nasopharyngeal swabs were tested as point-of-care tests. Discordant results and agreement between the two tests were evaluated.
Results: A total of 453 patients were analyzed from December 2023 to February 2025. Mean age was 50.6 ± 20.6 years; 239 (52.8 %) were male. Influenza was detected in 166 (36.6 %) patients. Mean time from symptom onset to testing was 32.4 ± 62.1 h. Rapid NAAT-positive but RAT-negative cases were significantly more frequent (P < 0.001), supporting the higher sensitivity of the rapid NAAT. Cohen's kappa coefficient between tests was 0.750 (95 % CI 0.685-0.815, P < 0.001). This suggests systematic differences in sensitivity rather than random disagreement. Among patients tested within 48 h of symptom onset, discordance remained significant (P < 0.001).
Conclusion: In patients with suspected influenza in the emergency department, although rapid NAAT and RAT demonstrated good agreement, the cases that tested positive by the rapid NAAT but negative by the RAT were significantly more frequent. This suggests that rapid NAAT may be a more suitable diagnostic tool in the emergency department, as rapid NAAT can help avoid false negatives, enable timely antiviral treatment, and improve clinical decision-making within the critical treatment window.

Keywords: Emergency department; Influenza virus; POCT; Rapid antigen test; Rapid molecular assays.

 
Back
Top