Field Evaluation of the InBios Chagas Detect Plus Rapid Test in Serum and Whole-Blood Specimens in Bolivia

Abstract

h Trypanosoma cruzi causes Chagas disease, which affects an estimated 7 million to 8 million people. Chagas disease is endemic throughout Latin America, with the highest prevalence in Bolivia. Conventional diagnosis requires a well-equipped laboratory with experienced personnel. We evaluated the Chagas Detect Plus (CDP) (InBios, Seattle, WA), a rapid immunochromatographic assay for IgG antibodies to T. cruzi. CDP performance was compared to infection status based on results obtained by indirect hemagglutination assay, immunofluorescent-antibody test, and enzyme-linked immunosorbent assay. Confirmed infection required positive results by at least 2 conventional assays. We used specimens from adults of both sexes in a general hospital in the city of Santa Cruz and from pregnant women in a hospital and children in villages in the Bolivian Chaco, an area of hyperendemicity. CDP was performed in paired whole-blood and serum specimens from 385 individuals in the two hospital studies and in 200 serum specimens from the community study. CDP showed sensitivities/specificities of 96.2% (95% confidence interval, 92.7 to 98.4)/98.8% (95.9 to 99.9) in whole blood and 99.3% (97.5 to 99.9)/96.9% (94.2 to 98.6) in serum, with no differences by sex, age group, or study site. CDP showed excellent sensitivity and specificity in our study population, comparable to those of conventional serology. The test is reliable for field surveys, requires no laboratory equipment, and performed well in serum and whole blood. The CDP could also be used for accurate maternal screening to identify neonates at risk of congenital transmission. CDP performance data in diverse geographic areas are needed to strengthen the evidence base for its use.

Chagas disease in the Bolivian Chaco: Persistent transmission indicated by childhood seroscreening study

“…This, coupled with the high FOI estimate, demonstrates significant recent vector transmission. Although the specificity of the CDP (91.9%) in this study was lower than that reported in previous analyses, screening in this rural village was greatly facilitated by the use of this rapid test (Eguez et al, 2017;Shah et al, 2014). Pairing a highly sensitive rapid test with a more specific confirmatory test allows efficient screening, even in a challenging community setting.…”

“…Children were screened using the Chagas Detect Plus (CDP) immunochromatographic assay (InBios International, Inc., Seattle, WA, USA). This assay has previously been shown to have sensitivity of 96.2% and specificity of 98.8% in a similar population in the Bolivian Chaco (Shah et al, 2014). Children with positive CDP results had venous blood drawn and tested by indirect haemagglutination assay (IHA) (Chagas Polychaco kit; Lemos Laboratories, Buenos Aires, Argentina) following national Chagas disease control protocols.…”

Rapid diagnostic tests duo as alternative to conventional serological assays for conclusive Chagas disease diagnosis

“…Therefore, in full agreement with others, RDTs must be field validated in each particular site before its use for screening is recommended [19,20]. Seroprevalence detected in this work was quite high (60.8%), but accordingly to the Bolivian government Chagas Management Departmental Program (with data from 2013), Chagas disease seroprevalence in the department of Chuquisaca was estimated to be 5.6% amongst children between 1–4 years old, 5.4% in the age range from 5 to 14 years old, and 56.6% in those ≥15 years old [23].…”

Trypanosoma cruzi infection in the human population of the Bolivian Chaco: four serosurveys over a 26-year period (1987-2013)

“…Relatively few studies reported data on CD epidemiology in the Bolivian Chaco, although it is acknowledged as one of the most affected areas in the planet. In Table 2, we report a summary of the main available studies concerning anti-T. cruzi antibodies seroprevalence in the human population of the Bolivian Chaco [9][10][11][12][13]. A detailed and accurate analysis of the epidemiological evolution is challenging, being hindered by several limitations.…”