Evaluation of the performance of two Chagas disease antibody tests in patients from the Chaco region (Argentina)

Abstract

Chagas disease (CD) is caused by the protozoan Trypanosoma cruzi and is a significantzoonotic disease affecting millions worldwide. The disease progresses from an oftenasymptomatic acute phase to a chronic phase, which can lead to severe cardiac ordigestive issues in about 30% of untreated individuals after 20 to 30 years. Earlydiagnosis and treatment are crucial to managing the disease and preventing furthertransmission. Diagnosis typically involves serological tests to detect anti-T. cruziantibodies, with the Indirect Hemagglutination Assay (IHA) and ELISA being the mostcommon methods. Given the antigenic diversity of the parasite, the Pan American HealthOrganization (PAHO) recommends the use of two different tests for a reliable diagnosis.The objective of the present study was to evaluate the performance of two commercialdiagnostic assays for chronic CD in the Chaco Region. Blood samples were collectedfrom 388 patients from the Chaco Region between November 2019 and November 2023,and the results showed a high degree of agreement between the IHA and Lysate ELISAcommercial tests. However, Lysate ELISA was found to produce more false negativescompared to the PAHO diagnostic algorithm, which could leave patients untreated andcontribute to ongoing transmission. The study demonstrated very good performance ofthe commercial tests evaluated. However, the presence of some false results underscoresthe importance of continuing to use the PAHO algorithm based on two serological testsfor reliable diagnosis in the region.