Performance evaluation of the LumiraDx SARS-CoV-2 & Flu A/B Test in diagnosing COVID-19 and influenza in patients with respiratory symptoms

Abstract

Introduction Coronavirus disease 2019 (COVID-19) and influenza share similar symptoms, which hampers diagnosis. Given that they require different containment and treatment strategies, fast and accurate distinction between the two infections is needed. This study evaluates the sensitivity and specificity of the LumiraDx SARS-CoV-2 & Flu A/B Test for simultaneous detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza A/B from a single nasal swab. Methods Nasal samples were collected from patients as part of the ASPIRE (NCT04557046) and INSPIRE (NCT04288921) studies at point-of-care testing sites in the USA. ASPIRE study participants were included after developing COVID-19 symptoms in the last 14 days or following a positive SARS-CoV-2 test in the last 48 hours. INSPIRE study participants were included after developing influenza symptoms in the last 4 days. Samples were extracted into proprietary buffer and analysed using the LumiraDx SARS-CoV-2 & Flu A/B Test. A reference sample was taken from each subject, placed into universal transport medium and tested using reference SARS-CoV-2 and influenza reverse transcription polymerase chain reaction (RT-PCR) tests. The test and reference samples were compared using the positive percent agreement (PPA) and negative percent agreement (NPA), together with their 95% confidence intervals (CI). Results Analysis of the data from the ASPIRE (N=124) and INSPIRE (N=159) studies revealed high levels of agreement between the LumiraDx SARS-CoV-2 & Flu A/B Test and the reference tests in detecting SARS-CoV-2 (PPA=95.5% [95% CI: 84.9%, 98.7%]; NPA=96.0% [95% CI: 90.9%, 98.3%]), influenza A (PPA=83.3% [95% CI: 66.4%, 92.7%]; NPA=97.7% [95% CI: 93.4%, 99.2%]) and influenza B (PPA=80.0% [95% CI: 62.7%, 90.5%]; NPA=95.3% [95% CI: 90.2%, 97.9%]). Conclusions The LumiraDx SARS-CoV-2 & Flu A/B Test shows a high agreement with the reference RT-PCR tests while simultaneously detecting and differentiating between SARS-CoV-2 and influenza A/B.