{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,18]],"date-time":"2026-02-18T09:01:08Z","timestamp":1771405268874,"version":"3.50.1"},"reference-count":12,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2026,2,17]],"date-time":"2026-02-17T00:00:00Z","timestamp":1771286400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Ministero della Salute, Ricerca Corrente","award":["08074882"],"award-info":[{"award-number":["08074882"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pathogens"],"abstract":"<jats:p>Congenital toxoplasmosis (CT) results from vertical transmission of Toxoplasma gondii during maternal infection in pregnancy. Early diagnosis in newborns is crucial to initiate timely therapy and prevent long-term sequelae. The IgM Immunosorbent Agglutination Assay (ISAGA) has historically been considered an important diagnostic tool for CT; however, its recent market withdrawal necessitates alternative approaches. We conducted a retrospective observational study at Fondazione IRCCS Policlinico San Matteo, Pavia, Italy, including 44 newborns born to mothers with confirmed toxoplasmosis between 2019 and 2022. Newborns were classified as CT (n = 19) or non-CT (n = 25) based on serological follow-up, comparative Western blot (CWB) and Interferon Gamma Release Assay (IGRA). Sensitivity and specificity of CWB, IgM Chemiluminescent Immunoassay (CLIA), and IgM ISAGA were assessed at birth and at one month. At birth, CWB demonstrated 88.9% sensitivity, significantly higher than IgM CLIA (52.6%) and IgM ISAGA (57.9%). Specificity was 100% at birth and 92% at one month. CWB retained high sensitivity at one month (81.8%). IGRA complemented CWB in confirming or excluding infection in cases with equivocal or false-negative serology. Comparative Western blot thus represents a robust diagnostic alternative for CT, ensuring early detection and timely treatment, particularly in the absence of IgM ISAGA.<\/jats:p>","DOI":"10.3390\/pathogens15020225","type":"journal-article","created":{"date-parts":[[2026,2,18]],"date-time":"2026-02-18T07:50:30Z","timestamp":1771401030000},"page":"225","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Comparative IgG-IgM Western Blot in the Diagnosis of Congenital Toxoplasmosis: A Valid Diagnostic Tool"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0009-0001-7304-0391","authenticated-orcid":false,"given":"Alice","family":"Bonetti","sequence":"first","affiliation":[{"name":"Microbiology and Virology Unit, Diagnostic Medicine Department, Fondazione IRCCS Policlinico San Matteo, 27100 Pavia, Italy"},{"name":"PhD National Programme in One Health Approaches to Infectious Diseases and Life Science Research, Department of Public Health, Experimental and Forensic Medicine, University of Pavia, 27100 Pavia, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9657-5084","authenticated-orcid":false,"given":"Ambra","family":"Vola","sequence":"additional","affiliation":[{"name":"Microbiology and Virology Unit, Diagnostic Medicine Department, Fondazione IRCCS Policlinico San Matteo, 27100 Pavia, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7747-7622","authenticated-orcid":false,"given":"Daniele","family":"Lilleri","sequence":"additional","affiliation":[{"name":"Microbiology and Virology Unit, Diagnostic Medicine Department, Fondazione IRCCS Policlinico San Matteo, 27100 Pavia, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lucrezia","family":"Lo Grasso","sequence":"additional","affiliation":[{"name":"Microbiology and Virology Unit, Diagnostic Medicine Department, Fondazione IRCCS Policlinico San Matteo, 27100 Pavia, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Milena","family":"Furione","sequence":"additional","affiliation":[{"name":"Microbiology and Virology Unit, Diagnostic Medicine Department, Fondazione IRCCS Policlinico San Matteo, 27100 Pavia, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Alessia","family":"Arossa","sequence":"additional","affiliation":[{"name":"Department of Obstetrics and Gynecology, Fondazione IRCCS Policlinico San Matteo, 27100 Pavia, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5784-0770","authenticated-orcid":false,"given":"Alessandra","family":"Ricciardi","sequence":"additional","affiliation":[{"name":"Infectious Diseases Unit, Fondazione IRCCS Policlinico San Matteo, 27100 Pavia, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Claudia","family":"Vigan\u00f2","sequence":"additional","affiliation":[{"name":"Neonatalogy and Neonatal Intensive Care Unit, Fondazione IRCCS Policlinico San Matteo, 27100 Pavia, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Alessia","family":"Bressan","sequence":"additional","affiliation":[{"name":"Microbiology and Virology Unit, Diagnostic Medicine Department, Fondazione IRCCS Policlinico San Matteo, 27100 Pavia, Italy"},{"name":"PhD National Programme in One Health Approaches to Infectious Diseases and Life Science Research, Department of Public Health, Experimental and Forensic Medicine, University of Pavia, 27100 Pavia, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Claudia","family":"Pavia","sequence":"additional","affiliation":[{"name":"Microbiology Unit, Department of Laboratory Medicine and Diagnostic Biotechnology, Azienda Socio Sanitaria Territoriale (ASST) Ovest Milanese, Hospital of Legnano, 20025 Milan, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3128-8441","authenticated-orcid":false,"given":"Annalisa","family":"De Silvestri","sequence":"additional","affiliation":[{"name":"Scientific Direction, Clinical Epidemiology and Biometric Unit, Fondazione IRCCS Policlinico San Matteo, 27100 Pavia, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-0795-7972","authenticated-orcid":false,"given":"Giulia","family":"Gambini","sequence":"additional","affiliation":[{"name":"Scientific Direction, Clinical Epidemiology and Biometric Unit, Fondazione IRCCS Policlinico San Matteo, 27100 Pavia, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Fausto","family":"Baldanti","sequence":"additional","affiliation":[{"name":"Microbiology and Virology Unit, Diagnostic Medicine Department, Fondazione IRCCS Policlinico San Matteo, 27100 Pavia, Italy"},{"name":"Department of Clinical, Surgical, Diagnostic and Pediatric Sciences, University of Pavia, 27100 Pavia, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Valeria","family":"Meroni","sequence":"additional","affiliation":[{"name":"Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,2,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"583","DOI":"10.1128\/CMR.00026-12","article-title":"Epidemiology of and diagnostic strategies for toxoplasmosis","volume":"25","year":"2012","journal-title":"Clin. 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