[Evaluation of a change in the serological diagnostic algorithm for Chagas disease in ColombiaAvaliação da mudança do algoritmo de diagnóstico sorológico da doença de Chagas na Colômbia].

Objective: To evaluate the effects of changing the algorithm for serological diagnosis of Methods: A descriptive, cross-sectional study was carried out, based on secondary sources between 2015 and 2021, consolidating the number of serological tests carried out by the laboratories. A survey was developed to identify benefits and limitations in the implementation of the new algorithm for serological diagnosis. Totals, proportions, and averages of the number of tests were estimated by comparing two different periods. Results: Information from 33 public health laboratories was analyzed, 87.9% of which processed serological assays during the period under study. The use of serological tests increased after the publication of the new guideline in 2017, and the capacity to perform the second test increased from four to 33 public health laboratories. In absolute terms, ELISAs for antigens and recombinant antigens became the most performed tests in Colombia after 2017. Conclusions: The change in the algorithm for serological diagnosis of Chagas disease in Colombia in 2017 had positive effects on access to diagnosis since it facilitated the use of the second test. This change resulted in increased diagnostic coverage. The country's laboratories have access to a simple, timely, quality algorithm that could be implemented in almost any clinical laboratory in the country.