Development of an indirect immunofluorescence assay for SARS-CoV-2 nasopharyngeal samples

Development of an indirect immunofluorescence assay for SARS-CoV-2 nasopharyngeal samples | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Method Article Development of an indirect immunofluorescence assay for SARS-CoV-2 nasopharyngeal samples Gabriel Martin, Fátima Abreu-Salinas This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6456821/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract During the last pandemic situation, availability of the widest possible range of diagnostic techniques was really important. Nowadays, RT-qPCR is the gold-standard, but those techniques based on immunochromatography for SARS-CoV-2 antigen detection are the most used for quick patient triage. However, there are other techniques for antigen detection that may be useful, as indirect immunofluorescence assays (IFA). The aim of this study is to stablish an IFA method for SARS-CoV-2 detection on direct nasopharyngeal samples. Results show total sensitivities between 34.55% and 39.70%, with specificities between 72% and 88%. So, these data allow similar results for in-house IFA techniques than for immunochromatographic tests available nowadays. General Microbiology Immunofluorescence Assay Indirect IFA SARS-CoV-2 Full Text Additional Declarations The authors declare no competing interests. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6456821","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Method Article","associatedPublications":[],"authors":[{"id":443417269,"identity":"88db68e6-d303-47e8-b7d3-cf58d5a936dd","order_by":0,"name":"Gabriel Martin","email":"data:image/png;base64,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","orcid":"","institution":"Hospital Universitario Central de Asturias","correspondingAuthor":true,"prefix":"","firstName":"Gabriel","middleName":"","lastName":"Martin","suffix":""},{"id":443417332,"identity":"b9a7f707-e802-41ea-98df-7797ca15eac0","order_by":1,"name":"Fátima Abreu-Salinas","email":"","orcid":"","institution":"Hospital Universitario Central de Asturias","correspondingAuthor":false,"prefix":"","firstName":"Fátima","middleName":"","lastName":"Abreu-Salinas","suffix":""}],"badges":[],"createdAt":"2025-04-15 16:49:15","currentVersionCode":1,"declarations":{"humanSubjects":false,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-6456821/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6456821/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":80711941,"identity":"b2c8325d-387b-436c-8862-5d29f216339b","added_by":"auto","created_at":"2025-04-16 09:09:38","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":470710,"visible":true,"origin":"","legend":"","description":"","filename":"Manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6456821/v1_covered_da3fcc45-cd38-4c8a-ae91-6ad791f94fc0.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003eDevelopment of an indirect immunofluorescence assay for SARS-CoV-2 nasopharyngeal samples\u003c/p\u003e","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"Hospital Universitario Central de Asturias","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Immunofluorescence Assay, Indirect IFA, SARS-CoV-2","lastPublishedDoi":"10.21203/rs.3.rs-6456821/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6456821/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eDuring the last pandemic situation, availability of the widest possible range of diagnostic techniques was really important. 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