Diagnostic Performance of Chimeric Recombinant Antigens of Trypanosoma cruzi for Identifying Chagas Disease in Samples From Rio Grande do Sul.

Chagas disease, caused by Trypanosoma cruzi, remains a significant public health challenge in Latin America, with diagnostic limitations hindering control efforts. Our study aimed to assess the diagnostic performance of four chimeric recombinant T. cruzi antigens (IBMP-8.1, IBMP-8.2, IBMP-8.3 and IBMP-8.4) in a highly endemic region in southern Brazil. Serum samples from 333 individuals residing in Canguçu, Rio Grande do Sul, were tested using an in-house ELISA platform. We assessed the sensitivity, specificity, accuracy, and diagnostic odds ratio (DOR) of individual and combined IBMP antigens through serial and parallel testing strategies. All antigens exhibited 100% specificity and high accuracy (≥ 93.4%), with IBMP-8.1 and IBMP-8.4 showing the best overall performance (sensitivities of 80.0% and 76.7%; DORs of 109,136 and 89,659, respectively). Parallel testing using the combinations IBMP-8.1 + IBMP-8.3 and IBMP-8.1 + IBMP-8.4 achieved ≥ 95% sensitivity and > 99% accuracy. These findings support the use of IBMP chimeric antigens, particularly in combination, as reliable tools for Chagas disease diagnosis and surveillance, and highlight the importance of region-specific validation to ensure diagnostic equity in diverse endemic settings.