BRIEF RESEARCH REPORT article
Front. Public Health
Sec. Infectious Diseases: Epidemiology and Prevention
This article is part of the Research TopicWorld TB Day 2025: Yes! We Can End TB: Commit, Invest, DeliverView all 17 articles
Performance Evaluation of the AFIAS IGRA-TB (IFN-gamma) Test Versus QuantiFERON®- TB Gold Plus (QFT®-Plus) ELISA in the Barrio Obrero Hospital Network, Asunción – Paraguay, 2025
Provisionally accepted
Cynthia Céspedes1,2Jessica Riveros1,2Antonio Villalba2Sandra Gutierrez2Roxana Ocampo2Adán Godoy2Sarita Aguirre1,2
Angélica Medina1,3
Guillermo Sequera3,4*- 1Programa Nacional de Control de la Tuberculosis, Asunción, Paraguay
- 2Hospital General de Barrio Obrero, Asunción, Paraguay
- 3Universidad Central del Paraguay, Asunción, Paraguay
- 4Faculty of Medical Sciences, National University of Asunción, Asunción, Paraguay
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Background: Tuberculosis infection affects an estimated one-quarter of the global population and represents a key target for TB elimination strategies. While interferon-gamma release assays (IGRAs) such as QuantiFERON-TB Gold Plus (QFT-Plus) are WHO-endorsed, they remain logistically complex in low-resource settings. This study evaluates the performance of the AFIAS IGRA-TB, a qualitative fluorescence immunoassay (FIA), compared to QFT-Plus in Paraguay. Methods: A cross-sectional diagnostic accuracy study was conducted from January to May 2025 among 210 individuals aged 18–59 years within the Barrio Obrero healthcare network in Asunción, Paraguay. Participants were stratified into three TB risk groups: low-risk (no known exposure), high-risk (close contacts and incarcerated individuals), and active TB cases. Blood samples were tested with both AFIAS and QFT-Plus assays. Discordant results were retested after six to eight weeks. Concordance was assessed using Cohen's Kappa; quantitative correlations and ROC curves were also analysed. Results: Of 210 participants, 75.2% were male. Overall positivity rates were 38.5% for QFT-Plus and 37.0% for AFIAS, with an agreement of 89.0% (κ = 0.767; p < 0.0001). Strong concordance was observed in high-risk groups. Among 23 discordant cases, retesting confirmed the initial AFIAS result in 5 cases and QFT-Plus in 3; 7 remained discordant. Spearman correlation showed strong, significant association between quantitative values. ROC analysis yielded an AUC of 0.890 for AFIAS. Conclusions: AFIAS IGRA-TB demonstrates comparable performance to QFT-Plus with operational advantages, suggesting it is a viable diagnostic alternative for TB infection, particularly in decentralized or resource-limited settings.
Keywords: Diagnostic Techniques andProcedures3, DiagnosticTechniques and Procedures, Interferon-gamma Release Tests, Interferon-gamma Release Tests2, Latent, Main Terms: Tuberculosis, Point-of-Care Testing4, Tuberculosis infection5
Received: 21 Oct 2025; Accepted: 11 Dec 2025.
Copyright: © 2025 Céspedes, Riveros, Villalba, Gutierrez, Ocampo, Godoy, Aguirre, Medina and Sequera. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Guillermo Sequera
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