Abstract

SANABRIA, Arianna et al. Evaluation of a latex-streptavidin-tp17 agglutination assay prototype for detection of anti-Treponema pallidum antibodies. Mem. Inst. Investig. Cienc. Salud [online]. 2023, vol.21, n.1, e21122306.  Epub May 12, 2023. ISSN 1812-9528.  https://doi.org/10.18004/mem.iics/1812-9528/2023.e21122306.

Syphilis is a bacterial infection caused by Treponema pallidum. Diagnosis is based on clinical features and indirect serological laboratory tests. The objective was to evaluate a latex-streptavidin-Tp17 agglutination assay prototype for the detection of anti-T. pallidum antibodies. The optimal conditions of a agglutination assay prototype based on streptavidin-coated polystyrene latex particles and a biotinylated Tp17 were standardized. The concordance of the assay with other commercial tests was analyzed to determine its usefulness as an alternative in the diagnosis of syphilis. The optimal conditions for the reagents preparation were obtained and the reagent stability was demonstrated for up to 90 days stored at 4ºC. Regarding the concordance between the prototype and other commercial tests, 56 samples were analyzed with the VDRL test and a kappa index of 0.48 CI95% (0.24-0.73) was obtained, indicating a moderate agreement. Also, 44 samples, previously evaluated by chemiluminescence (CLIA), were evaluated with the assay, and a kappa index of 0.81 CI95% (0.55-1) was obtained demonstrating an almost perfect strength of agreement. Additionally, sensitivity and specificity were determined using the CLIA method as reference due to the similarity in the use of the Tp17 antigen in both methods, and 94.87% and 100% were obtained respectively. These results suggest further evaluation of the assay performance oriented to a possible application in the general population.

Keywords : Agglutination; concordance; recombinant protein; syphilis.

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