Overall serum value distribution of ELISAc (A), ELISAr (B), and Architect Chagas (C). Serum samples from panel I (samples from chronic chagasic seropositive patients, n = 107), panel II (samples from nonchagasic patients, n = 125), panel III (samples with discrepant serological results, n = 12), and panel IV (samples from patients with other infections, n = 71) are represented. Filled circles (●) indicate true-positive and negative results, open circles (○) indicate false-positive and negative results, and Xs (×) represent results in the gray zone. Dashed lines represent the cutoff value established for each test: 20 units for ELISAc (A), 1 absorbance/cutoff value for ELISAr (B), and 1 relative light unit/cutoff value for Architect Chagas (C). The dotted line in panel C indicates the point of the 6 relative light units/cutoff value on the y axis.