Precisión discriminatoria de pruebas serológicas para Trypanosoma cruzi aplicando metodología estándar y de curva COR

Introduction: Serological tests are used to confirm Trypanosoma cruzi infection and their discriminatory accuracy depends on the established decision threshold. Both, the standard methodology and the receiver operating characteristic (ROC) curve methodology allow obtaining such threshold. Objective: To compare the discriminatory accuracy of the standard methodology and the ROC curve methodology regarding serological tests for cofirming T. cruzi infection. Materials and methods: A set of anti- T. cruzi antibodies values from subjects previously classified as healthy or as having Chagas disease were used, and computer simulations were performed in homoscedasticity and heteroscedasticity conditions. Sensitivity, specificity, 100% sensitivity, 100% specificity, and perfect-decision were calculated. Results: The discriminatory accuracy obtained with the standard methodology favored specificity (98.22% to 99.56%) over sensitivity (67.25% to 87.14%), while in the ROC curve methodology a balance balance between sensitivity (94.56% and 96.44%) and specificity (90.35% and 92.11%) was observed. Also, in the ROC curve methodology a greater perfect-decision ratio was observed, which, under homoscedasticity conditions, was >90%. Decisions thresholds were affected by heterocedasticity conditions. Conclusion: The ROC curve methodology showed a better discriminatory accuracy, therefore its use for calculating decision thresholds in serological tests for detecting Chagas disease is recommended.