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Performance differences among commercially available antigen rapid tests for COVID-19 in Brazil
Mariana Lourenço Freire1, Lindicy Leidicy Alves1, Carolina Senra de Souza1,2
1Pesquisa Clínica e Políticas Públicas em Doenças Infecciosas e Parasitárias, Instituto René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil.
Plos One
|June 16, 2022
Summary
Rapid antigen detection tests (Ag-RDTs) offer a faster alternative to RT-qPCR for COVID-19 diagnosis. While sensitivity varies, Ag-RDTs are valuable for prompt diagnosis in high-viral-load patients, aiding immediate management and reducing transmission.
Area of Science:
- Infectious Diseases
- Diagnostic Technologies
- Public Health
Background:
- Rapid and accurate diagnosis is essential for controlling the COVID-19 pandemic.
- Antigen detection rapid diagnostic tests (Ag-RDTs) offer a faster alternative to RT-qPCR, especially when scaling up testing is challenging.
- Performance evaluation of commercially available Ag-RDTs is crucial, particularly in diverse geographical settings.
Purpose of the Study:
- To evaluate the diagnostic performance of eight commercially available Ag-RDTs for COVID-19 in Brazil.
- To compare the sensitivity and specificity of Ag-RDTs against RT-qPCR.
- To assess the influence of viral load and disease duration on Ag-RDT performance.
Main Methods:
- Eight different Ag-RDTs were evaluated using a masked protocol on patients admitted to tertiary hospitals with COVID-19 symptoms.
- All tests were performed strictly following manufacturer instructions.
- Results were compared with RT-qPCR as the gold standard.
Main Results:
- Overall sensitivity of Ag-RDTs ranged from 9.8% to 81.1%, with specificity consistently above 83%.
- Most Ag-RDTs showed slight or fair agreement with RT-qPCR, except for one showing moderate agreement.
- Ag-RDT sensitivity was lower in patients with a cycle threshold > 25, indicating a direct correlation with viral load.
Conclusions:
- Despite lower sensitivity compared to RT-qPCR, Ag-RDTs are valuable for rapid COVID-19 diagnosis, especially upon hospital admission.
- Ag-RDTs enhance access to diagnosis for patients with high viral loads, enabling timely clinical management.
- The promptness and ease of use of Ag-RDTs support their role in reducing infectivity and community transmission of COVID-19.
