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The following is a summary of “Multiplex lateral flow test sensitivity and specificity in detecting influenza A, B and SARS-CoV-2 in adult patients in a UK emergency department,” published in the January 2025 issue of Emergency Medicine by Batra et al. 

Rapid identification of individuals with acute respiratory infections is essential for preventing nosocomial infections, with multiplex lateral flow devices (M-LFDs) offering a convenient and cost-effective diagnostic solution in emergency departments (EDs).  

Researchers conducted a retrospective study to compare the real-world performance of M-LFDs devices and PCR testing in detecting influenza A, B, and SARS-CoV-2 in emergency settings.  

They conducted an initial evaluation of a M-LFD, SureScreen using laboratory-grown viruses and PCR-negative samples, followed by real-world testing in the ED of St Thomas’ Hospital (London, UK) from 1 December 2022 to 21 April 2023. Participants included adults (≥18 years) with respiratory symptoms undergoing both M-LFD and PCR testing. Sensitivity to detect influenza A/B (primary) and SARS-CoV-2 (secondary) was compared to PCR results. Logistic regression analyzed the likelihood of true positives based on viral concentration, expressed as PCR cycle threshold (Ct).  

The results showed 808 symptomatic individuals (49.8% female; mean age 46.9 years) were included. Test sensitivity (95% CI) was 67.0% (56.9% to 76.1%) for influenza A (n=100), 94.1% (71.3% to 99.9%) for influenza B (n=17), and 48.2% (39.7% to 56.8%) for SARS-CoV-2 (n=141). Sensitivity for SARS-CoV-2 was lower than for influenza A (P =0.0057) and influenza B (P =0.00088). True positive probability was 98% for Ct <25 for influenza A and SARS-CoV-2 (influenza B non-evaluable). No co-infections were detected by PCR or M-LFD.  

Investigators concluded the SureScreen M-LFD illustrated real-world performance consistent with laboratory findings, achieving high sensitivity in individuals with high viral concentrations and supporting its broader applicability in similar settings. 

Source: emj.bmj.com/content/early/2025/01/14/emermed-2024-214177