Laboratory evaluation of five rapid diagnostic tests for the serological diagnosis of chronic Trypanosoma cruzi infection in Yucatán, Mexico
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Chagas disease (CD), caused by Trypanosoma cruzi , is a significant public health challenge in Latin America, where an estimated 70% of infected individuals remain undiagnosed. Rapid diagnostic tests (RDTs) offer a promising solution for new screening strategies, yet their performance has not been systematically assessed in Mexican cohorts.
Here, we evaluated the diagnostic performance of five RDTs: Chagas Rapid Test (Certum), Bio-Chagas Rapid Test (Mexlab), Bioline TM Chagas Ab (Abbott), Chagas Rapid Test (Amunet) and Chagas Sero K -SeT (Coris BioConcept). Performance was tested using 79 archived human serum samples from Yucatán. All tests were benchmarked against the diagnostic reference algorithm established by the Mexican Official Norm ( NOM ), where samples were characterised as positive if they were reactive to ≥ 2 conventional serological assays (Chagatest Lisado , Chagatest Recombinante v4.0 and Chagatest HAI).
The RDTs demonstrated variable diagnostic sensitivity. The Bioline TM Chagas Ab test demonstrated the highest sensitivity (97.2%, 95% CI: 85.5 - 99.9; 35/36 positive samples detected) and almost perfect statistical agreement with the NOM reference algorithm (κ= 0.90; p < 0.0001). Similarly, the Chagas Sero K -SeT prototype showed a high sensitivity (91.7%, 95% CI: 77.5 – 98.2; 33/36 positive samples detected) and substantial concordance (κ= 0.87, p < 0.0001) with the NOM -based composite result. In contrast, the remaining RDTs demonstrated low sensitivities (Certum: 0.0%, 95% CI: 0.0–9.7; Mexlab: 5.6%, 95% CI: 0.7–18.7; Amunet: 33.3%, 95% CI: 18.6–51.0), limiting their suitability for CD diagnostic algorithms, at least in Yucatán. Specificity was consistently high across the RDTs, ranging from 93.0% to 100% (95% CIs: 80.9–100). These findings underscore the need to locally validate diagnostic tools. The Bioline TM Chagas Ab and Chagas Sero K -SeT tests met the WHO benchmarks for RDT performance and, if validated in larger cohorts, could strengthen the screening of T. cruzi infection and epidemiological surveillance in Mexico.
Author summary
Chagas disease, caused by the parasite Trypanosoma cruzi , remains underdiagnosed in Mexico. Rapid diagnostic tests (RDTs) could help expand access to screening, particularly in settings where laboratory testing is difficult to implement. However, the performance of these tests can vary geographically and has not been systematically evaluated in Mexico.
We evaluated four commercially available RDTs and one developmental prototype using archived serum samples from Yucatán, a region where Chagas disease is endemic. Results were compared with the diagnostic algorithm recommended by the Mexican Official Norm.
The Bioline™ Chagas Ab test showed the highest sensitivity, detecting 35 of 36 positive samples, while the Chagas Sero K-SeT prototype detected 33. The other three commercial RDTs showed substantially lower sensitivity, detecting between 0 and 12 positive samples. Specificity was high across all five tests, ranging from 93.0% to 100%, indicating that most negative samples were correctly identified. However, the low sensitivity of three tests limits their usefulness for Chagas disease screening in Yucatán.
Our findings highlight the importance of locally validating RDTs before their implementation. The Bioline TM Chagas Ab and Chagas Sero K -SeT tests show promise for Chagas disease screening in Mexico but require further evaluation using larger and geographically diverse cohorts.
