Concordance of Results by Three Chagas Disease Antibody Assays in US Clinical Specimens

Confirmed diagnosis of chronic Trypanosoma cruzi infection requires positive results by two distinct serological tests (1, 2). Test performance varies by assay and geographic origin of the infection (3–5). Previously, we reported the performance of the four Chagas disease (CD) immunoassays cleared by the US Food and Drug Administration (FDA) (3). That evaluation was performed on plasma aliquots from U.S. blood donations, which are a different matrix from clinical serum specimens. Additionally, blood donors tend to be younger and healthier than clinical populations; both of these these factors could affect real-world test performance. Here, we present an updated evaluation of two previously assessed CD diagnostic assays and one novel CD assay in serum samples from a commercial reference laboratory that may better reflect clinical populations in the United States.