Brazilian Journal of Infectious Diseases (May 2025)
Real-world accuracy of SARS-CoV-2 antigen detection compared with qPCR: A cross-sectional study in Toledo - PR, Brazil
- Carla Adriane Royer,
- Regis Goulart Rosa,
- Maicon Falavigna,
- Jaqueline Carvalho de Oliveira,
- Mariana Motta Dias da Silva,
- Carolina Gracia Poitevin,
- Hellen Abreu,
- Valter Antonio Baura,
- Ana Claudia Bonatto,
- Daniela Fiori Gradia,
- Cristina de Oliveira Rodrigues,
- Rafael Messias Luiz,
- Ana Paula Carneiro Brandalize,
- Josélia Larger Manfio,
- Cintia Laura Pereira de Araujo,
- Ana Paula de Souza,
- Daniel Sganzerla,
- Caroline Cabral Robinson,
- Fernanda Kelly Romeiro Silva,
- Gabriela Almeida Kucharski,
- Fernando Pedrotti,
- Srinivas Rao Valluri,
- Amit Srivastava,
- Viviane Wal Julião,
- Olga Chameh Melone,
- Florence Lefebvre d'Hellencourt,
- Moe H Kyaw,
- Julia Spinardi,
- Graciela del Carmen Morales Castillo,
- Emanuel Maltempi de Souza
Affiliations
- Carla Adriane Royer
- Department of Genetics; Federal University of Parana (UFPR); Curitiba, (PR), Brazil
- Regis Goulart Rosa
- Research Unit, Inova Medical, Porto Alegre, RS, Brazil; Research Institute, Hospital Moinhos de Vento (HMV), Porto Alegre, RS, Brazil; Internal Medicine Department, HMV, Porto Alegre, RS, Brazil
- Maicon Falavigna
- Research Unit, Inova Medical, Porto Alegre, RS, Brazil; Research Institute, Hospital Moinhos de Vento (HMV), Porto Alegre, RS, Brazil; Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Ontario, Canada
- Jaqueline Carvalho de Oliveira
- Department of Genetics; Federal University of Parana (UFPR); Curitiba, (PR), Brazil; Correspondence author at. Department of Genetics; Federal University of Parana; Curitiba, 81531-980, Brazil.
- Mariana Motta Dias da Silva
- Research Institute, Hospital Moinhos de Vento (HMV), Porto Alegre, RS, Brazil.
- Carolina Gracia Poitevin
- Department of Genetics; Federal University of Parana (UFPR); Curitiba, (PR), Brazil.
- Hellen Abreu
- Department of Genetics; Federal University of Parana (UFPR); Curitiba, (PR), Brazil.
- Valter Antonio Baura
- Department of Biochemistry and Molecular Biology, UFPR, Curitiba, PR, Brazil
- Ana Claudia Bonatto
- Department of Genetics; Federal University of Parana (UFPR); Curitiba, (PR), Brazil.
- Daniela Fiori Gradia
- Department of Genetics; Federal University of Parana (UFPR); Curitiba, (PR), Brazil.
- Cristina de Oliveira Rodrigues
- Faculty of Medicine - Campus Toledo, UFPR, Brazil
- Rafael Messias Luiz
- Faculty of Medicine - Campus Toledo, UFPR, Brazil
- Ana Paula Carneiro Brandalize
- Faculty of Medicine - Campus Toledo, UFPR, Brazil
- Josélia Larger Manfio
- Research Institute, Hospital Moinhos de Vento (HMV), Porto Alegre, RS, Brazil.
- Cintia Laura Pereira de Araujo
- Research Institute, Hospital Moinhos de Vento (HMV), Porto Alegre, RS, Brazil.
- Ana Paula de Souza
- Research Institute, Hospital Moinhos de Vento (HMV), Porto Alegre, RS, Brazil.
- Daniel Sganzerla
- Research Unit, Inova Medical, Porto Alegre, RS, Brazil.; Research Institute, Hospital Moinhos de Vento (HMV), Porto Alegre, RS, Brazil.
- Caroline Cabral Robinson
- Research Unit, Inova Medical, Porto Alegre, RS, Brazil.
- Fernanda Kelly Romeiro Silva
- Research Institute, Hospital Moinhos de Vento (HMV), Porto Alegre, RS, Brazil.
- Gabriela Almeida Kucharski
- Department of Health of Toledo, Toledo, PR, Brazil
- Fernando Pedrotti
- Department of Health of Toledo, Toledo, PR, Brazil
- Srinivas Rao Valluri
- Pfizer, Vaccines Medical and Scientific Affairs – Emerging Markets, Collegeville, PA, USA
- Amit Srivastava
- Pfizer, Vaccines Medical and Scientific Affairs – Emerging Markets, Collegeville, PA, USA; Orbital Therapeutics, Cambridge, MA, USA
- Viviane Wal Julião
- Pfizer, Vaccines Medical and Scientific Affairs – Emerging Markets, Collegeville, PA, USA
- Olga Chameh Melone
- Pfizer, Vaccines Medical and Scientific Affairs – Emerging Markets, Collegeville, PA, USA
- Florence Lefebvre d'Hellencourt
- Pfizer, Vaccines Medical and Scientific Affairs – Emerging Markets, Collegeville, PA, USA
- Moe H Kyaw
- Pfizer, Vaccines Medical and Scientific Affairs – Emerging Markets, Collegeville, PA, USA
- Julia Spinardi
- Pfizer, Vaccines Medical and Scientific Affairs – Emerging Markets, Collegeville, PA, USA
- Graciela del Carmen Morales Castillo
- Pfizer, Vaccines Medical and Scientific Affairs – Emerging Markets, Collegeville, PA, USA
- Emanuel Maltempi de Souza
- Department of Biochemistry and Molecular Biology, UFPR, Curitiba, PR, Brazil
- DOI
- https://doi.org/10.1016/j.bjid.2025.104520
- Journal volume & issue
-
Vol. 29,
no. 3
p. 104520
Abstract
Rapid Antigen Tests (Ag-RDTs) for the detection of SARS-CoV-2 is an important diagnostic tool for containing virus spread. However, their accuracy ‒ the proportion of correct results (both true positives and true negatives) ‒ still needs to be proven when used in a real large-scale context. Accordingly, we provide data from a cross-sectional study conducted in Toledo - PR, Brazil, on the accuracy of rapid tests compared with qPCR within the Brazilian Unified Health System. A total of 2882 thousand individuals presenting symptoms suggestive of COVID-19 were screened. Overall, the antigen tests showed a sensitivity, specificity, and accuracy of 59 % (0.56‒0.62), 99 % (0.98‒0.99), and 82 % (0.81‒0.84) respectively. However, a significant difference was found when analysing two brand tests individually. In addition, for patients with a low quantification Cycle (Cq) < 20 (which indicates a high viral load), the agreement between test results was high (90.85 %). However, this agreement decreased significantly when the viral load decreased, dropping to 5.59 % for samples with Cq ≥ 33, which indicates a lower viral load. While rapid antigen tests are a valuable tool in combating virus spread, their accuracy can vary significantly between manufacturers and under conditions of low viral load.
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