Sensitivity and specificity of Chagas Stat-Pak test in Bolivia

To compare the results of an immunochromatographic test performed on whole blood, Chagas Stat-Pak, with those of an ELISA test using recombinant antigens.

We tested 995 subjects of a rural population of all ages in the south of Bolivia, 459 pregnant women of the same population and 1030 urban women giving birth from the east of Bolivia.

The sensitivity of the CSP test for the entire studied population (n = 2484) was 94.73% [93.35-96.10]; the specificity was 97.33% [96.50-98.15]. However, the specificity differed significantly between rural pregnant and urban birthing women, which could be attributed either to differences of parasite strain or Chagas prevalence.

The test is simple of use, reliable, relatively inexpensive (<2 US$ each test) and its performances are compatible with a field use for large-scale screenings.