Original Articles
Vol. 1 No. 2 (2025)
https://doi.org/10.4081/sjroh.2025.557

Performance of anti-SARS-CoV-2 IgG/IgM rapid diagnostic test in N’Djamena, Chad: evidence from a clinical perspective during an outbreak response

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Published: 9 October 2025
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COVID-19, rapid diagnostic test, ELISA, anti-SARS CoV- 2, antibody

Authors

Amine Akouya
Laboratoire des Grandes Épidémies Tropicales, University Hospital Complex “Le Bon Samaritain”, N’Djamena, Chad.
Ezechiel Ngoufack Jagni Semengue
Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, Cameroon.
Koutaya Dezoumbe
Laboratoire des Grandes Épidémies Tropicales, University Hospital Complex “Le Bon Samaritain”, N’Djamena, Chad.
Noubaramadji Yamti Suitombaye
Laboratoire des Grandes Épidémies Tropicales, University Hospital Complex “Le Bon Samaritain”, N’Djamena, Chad.
Aleyo Zita Nodjikouambaye
Laboratoire des Grandes Épidémies Tropicales, University Hospital Complex “Le Bon Samaritain”, N’Djamena, Chad.
Carla Montesano
Department of Biology, Faculty of Sciences, University of Rome Tor Vergata, Italy.
Carlo Federico Perno
Faculty of Medicine, University Hospital Complex “Le Bon Samaritain”, N’Djamena, Chad.
Vittorio Colizzi
Laboratoire des Grandes Épidémies Tropicales, University Hospital Complex “Le Bon Samaritain”, N’Djamena, Chad.
Giulia Cappelli
Laboratoire des Grandes Épidémies Tropicales, University Hospital Complex “Le Bon Samaritain”, N’Djamena, Chad.
Joseph Fokam
josephpfokam@gmail.com
Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, Cameroon.

The utility of rapid serological tests for anti-SARS-CoV-2 antibodies, particularly in a tropical context, is not well-defined. We evaluated the performance of the Genrui IgG/IgM rapid diagnostic test (RDT; Genrui Biotech Inc., Shenzhen, China) against an enzyme-linked immunosorbent assay (ELISA), which serves as the gold standard. This cross-sectional study was conducted in N’Djamena, Chad, in July 2022. A total of 198 samples from individuals attending a facility for COVID-19 diagnosis were tested using both the Genrui RDT and the DIATHEVA COVID-19 IgG ELISA kit (DIATHEVA S.r.l., Fano, Italy). IgG seropositivity with ELISA was 84.8%, significantly higher than the 54% found with the RDT, representing a 30.8% difference. The RDT showed a sensitivity of 60% and a specificity of 80%, with poor agreement with ELISA (Cohen’s κ=0.22). Positive and negative predictive values (PPVs and NPVs) were 94% and 26%, respectively. The rapid IgM/IgG test from Genrui Biotech Inc. has a significantly suboptimal performance for detecting anti-SARS-CoV-2 antibodies. This highlights the need for performing ELISA on non-reactive RDT cases during serosurveys or post-vaccine response assessments.

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Supporting Agencies

The present study was supported by the MAGIS Foundation, the Italian Agency for Development Cooperation, and the European and Developing Countries Clinical Trials Partnership, EDCTP PERECT-Study RIA2020 EF3000.
Amine Akouya, Laboratoire des Grandes Épidémies Tropicales, University Hospital Complex “Le Bon Samaritain”, N’Djamena

Doctoral School of Advanced Sciences for Sustainable Development, Evangelic University of Cameroon, Bandjoun, Cameroon.

Koutaya Dezoumbe, Laboratoire des Grandes Épidémies Tropicales, University Hospital Complex “Le Bon Samaritain”, N’Djamena

Doctoral School of Advanced Sciences for Sustainable Development, Evangelic University of Cameroon, Bandjoun, Cameroon; Laboratory of Immunology, National Research Council, Rome, Italy.

Noubaramadji Yamti Suitombaye, Laboratoire des Grandes Épidémies Tropicales, University Hospital Complex “Le Bon Samaritain”, N’Djamena

Doctoral School of Advanced Sciences for Sustainable Development, Evangelic University of Cameroon, Bandjoun, Cameroon.

Carla Montesano, Department of Biology, Faculty of Sciences, University of Rome Tor Vergata

Faculty of Sciences and Technology, Evangelical University of Cameroon, Bandjoun, Cameroon.

Carlo Federico Perno, Faculty of Medicine, University Hospital Complex “Le Bon Samaritain”, N’Djamena

Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, Cameroon.

Vittorio Colizzi, Laboratoire des Grandes Épidémies Tropicales, University Hospital Complex “Le Bon Samaritain”, N’Djamena

Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, Cameroon; Laboratory of Immunology, National Research Council, Rome, Italy.

Giulia Cappelli, Laboratoire des Grandes Épidémies Tropicales, University Hospital Complex “Le Bon Samaritain”, N’Djamena

National Public Health Emergency Operations Coordination Centre, Yaoundé, Cameroon.

Joseph Fokam, Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1

Faculty of Health Sciences, University of Buea, Cameroon; Bambino Gesù Pediatric Hospital, Rome, Italy; National AIDS Control Committee, Ministry of Public Health, Yaoundé, Cameroon; Virology Laboratory, Chantal Biya International Reference Centre for Research on HIV and AIDS Prevention and Management, Yaoundé, Cameroon.

How to Cite



Performance of anti-SARS-CoV-2 IgG/IgM rapid diagnostic test in N’Djamena, Chad: evidence from a clinical perspective during an outbreak response. (2025). Sahelian Journal of Responsible One Health, 1(2). https://doi.org/10.4081/sjroh.2025.557
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