Evaluation of two immunochromatographic tests for the diagnosis of Chagas disease

Abstract

Introduction. American trypanosomiasis is a neglected parasitic disease that affects between seven and eight million people, mainly in 21 countries in the Americas, including Peru. It is necessary to have reliable, rapid and easy-to-use diagnostic tests in Chagas disease endemic areas as part of the strategy to control the disease. Objectives. To compare the performance of the OnSite Chagas Ab Rapid Immunochromatographic Rapid Test with the SD Bioline Chagas Ab Rapid Immunochromatographic Rapid Test in serum samples from Peruvian participants, using the indirect immunofluorescence test (IIF) and the enzyme-linked immunosorbent assay (ELISA) as reference for the diagnosis of Chagas disease. Methods. A Cross-sectional study carried out with 114 serum samples, of which 36 and 38 were positive and negative, respectively, by conventional serological methods (IFI and ELISA), and 40 corresponded to samples from patients with other parasitic infections (IFI and ELISA negative). Results. The specificity was 97,4% [95% confidence interval (CI) 95% CI = 90,0-99,8] and 98,7% [95% CI = 92,3-100], and the sensitivity was 83,3% [95% CI = 67,6-92,4] and 72,2% [95% CI = 55,8-84,2], for OnSite Chagas Ab Rapid test and SD Bioline Chagas Ab Rapid, respectively. The positive and negative predictive values were 93,8 [95% CI = 85,4-100] and 92,3 [95% CI = 86,4-98,2], respectively for OnSite Chagas Ab Rapid test and 96,3 [95% CI = 89,2-100] and 88,5 [81,8-95,2], respectively for SD Bioline Chagas Ab Rapid. The diagnostic efficiency of the tests varied between 90,4% and 92,9%. Conclusions. The sensitivities of both rapid immunochromatographic tests were low in the sample studied, therefore, they are inadequate to be incorporated as tools for the diagnosis or screening of the disease.