Evaluation of strategies for the diagnosis of Chagas disease in an endemic area: SaMi-Trop study

This study aims to evaluate strategies for diagnosing Chagas disease (CD) using rapid tests and risk questions in an endemic area. This is an analytical cross-sectional study conducted with 751 individuals from two municipalities in an endemic region for CD in the North of Minas Gerais State, Brazil. Participants answered a questionnaire with personal information and the risk criteria for CD infection recommended by the Clinical Protocol and Therapeutic Guidelines for Chagas disease (PCDT). Subsequently, they underwent capillary blood collection for the rapid diagnostic test (RDT). Individuals with a positive RDT result, along with negative controls, underwent venipuncture for serological testing. The mean age of participants was 51.4 (±18.2) years, most were female (n=434/57.8%). In the RDT, 699 (93.1%) individuals tested negative; of these, 109 (15.6%) underwent serology and 4 (3.7%) tested positive. Among the 52 (6.9%) individuals with a positive RDT result, 48 (94.1%) had their result confirmed by the serological tests. RDT result, age, and risk factors—except for blood transfusion before 1992—were statistically associated with positive serology for CD. The RDT demonstrated high sensitivity (0.92; 95% CI: 0.81–0.92) and specificity (0.97; 95%CI: 0.92–0.99).