[Diagnosis of intestinal amebiasis using coproscopic and immunological methods in a population sample in greater...

We compare diagnostic methods for Entamoeba histolytica in fecal samples from the city of Belém, Pará, Brazil. We analyze stool samples from children and adults (Group I); stool and serum samples from adults (Group II); and stool samples from children (Group III). In groups I and III, we used direct examination with lugol (DM), Faust et al (FM), and ELISA (detection of E. histolytica anti-GIAP coproantigen) and in group II, DM, iron hematoxylin staining (IHS), FM, ELISA, and the indirect immunofluorescence test (IFAT) for detection of IgG antibodies. Positivity was 10.50% by DM plus FM and 28.99% by ELISA. There was no correlation between positivity and age group. In Group II (n = 87), the positive rate was 4.59% by DM plus FM, 8.04% by IHS, 4.59% by IFAT, and 21.83% by ELISA. The ELISA test was the most sensitive for all groups. IFAT alone is still not a useful tool for diagnosis of E. histolytica infection. The ELISA test is simple, performed in one-third of cases used for IHS and IFAT, and greatly improves quality of diagnosis. We recommend this as the method of choice for diagnosis of suspected E. histolytica infection.