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False Positivity of Anti-SARS-CoV-2 Antibodies in Patients with Acute Tropical Diseases in Thailand
July 13, 2025
Diagnostic Dilemmas in Co-Endemic Regions
In areas where dengue and COVID-19 overlap, false positives could lead to misdiagnosis, wasted resources, and unnecessary anxiety. For example, a patient with dengue might be incorrectly isolated for COVID-19, delaying proper treatment .
Vaccine and Immunity Studies
False positives complicate serosurveys estimating COVID-19 immunity. If IgA/IgM tests are unreliable, IgG tests—though less prone to cross-reactivity—may better reflect true infection rates in tropical settings .
Table 2: Antibody Test Performance Across Studies
| Study | Sensitivity | Specificity | Accuracy |
|---|---|---|---|
| Liu et al. (2020) | 85.6% | 91% | 88.3% |
| Chisompola et al. (2024) | 73% | 98% | 88% |
Navigating the Challenges: Solutions and Innovations
Prioritize IgG Testing: IgG’s lower false positivity rate makes it more reliable in tropical regions .
Combine Testing Methods: Pair antibody tests with RT-PCR or antigen tests to confirm results .
Develop Pathogen-Specific Assays: Tailor tests to ignore antibodies from common local diseases .
Conclusion: Toward Smarter Serology in the Tropics
The Thai study underscores a critical gap in COVID-19 diagnostics: standard antibody tests falter where tropical diseases thrive. While IgG tests and techniques like urea dissociation offer partial solutions, global health efforts must prioritize:
Standardized Protocols: Reduce variability in test manufacturing and interpretation .
Localized Test Designs: Create assays optimized for regional pathogen profiles .
Public Education: Clarify the limitations of antibody testing to prevent misinterpretation.
As the world grapples with overlapping epidemics, understanding and addressing false positivity is not just a scientific challenge—it’s a lifeline for accurate diagnosis and equitable care.