BMC Infect Dis . Evaluating an app-guided self-test for influenza: lessons learned for improving the feasibility of study designs to evaluate self-tests for respiratory viruses

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BMC Infect Dis


. 2021 Jun 29;21(1):617.
doi: 10.1186/s12879-021-06314-1.
Evaluating an app-guided self-test for influenza: lessons learned for improving the feasibility of study designs to evaluate self-tests for respiratory viruses


Monica L Zigman Suchsland ¹ , Ivan Rahmatullah ² , Barry Lutz ² , Victoria Lyon ² , Shichu Huang ² , Enos Kline ² , Chelsey Graham ³ , Shawna Cooper ⁴ , Philip Su ⁴ , Sam Smedinghoff ⁴ , Helen Y Chu ² , Kara Sewalk ⁵ , John S Brownstein ⁵ , Matthew J Thompson ² , Seattle Flu Study investigators



Affiliations

• PMID: 34187397
• PMCID: PMC8240430
• DOI: 10.1186/s12879-021-06314-1

Free PMC article

Abstract

Background: Seasonal influenza leads to significant morbidity and mortality. Rapid self-tests could improve access to influenza testing in community settings. We aimed to evaluate the diagnostic accuracy of a mobile app-guided influenza rapid self-test for adults with influenza like illness (ILI), and identify optimal methods for conducting accuracy studies for home-based assays for influenza and other respiratory viruses.
Methods: This cross-sectional study recruited adults who self-reported ILI online. Participants downloaded a mobile app, which guided them through two low nasal swab self-samples. Participants tested the index swab using a lateral flow assay. Test accuracy results were compared to the reference swab tested in a research laboratory for influenza A/B using a molecular assay.
Results: Analysis included 739 participants, 80% were 25-64 years of age, 79% female, and 73% white. Influenza positivity was 5.9% based on the laboratory reference test. Of those who started their test, 92% reported a self-test result. The sensitivity and specificity of participants' interpretation of the test result compared to the laboratory reference standard were 14% (95%CI 5-28%) and 90% (95%CI 87-92%), respectively.
Conclusions: A mobile app facilitated study procedures to determine the accuracy of a home based test for influenza, however, test sensitivity was low. Recruiting individuals outside clinical settings who self-report ILI symptoms may lead to lower rates of influenza and/or less severe disease. Earlier identification of study subjects within 48 h of symptom onset through inclusion criteria and rapid shipping of tests or pre-positioning tests is needed to allow self-testing earlier in the course of illness, when viral load is higher.

Keywords: Accuracy; Influenza; Mobile application; Rapid diagnostic test; Self-test.