RESUMEN
An enzyme-linked immunosorbent assay (ELISA) was developed for the detection of IgG antibodies to purified sheep hydatic cyst fluid antigen in 56 sera of confirmed cases of hydatidosis. The cut-off value was determined using serum samples from 80 healthy persons, employing two serum dilutions (1:100 and 1:500) with two and three standard desviations (SD). This assay was compared with the indirect hemaglutination test (IHAT). The sensitivity of ELISA-IgG was 94,3 for percent, for hepatic cysts and 92,9 for percent, for pulmonary cysts, whereas the values for IHAT were 77,1 and 64,3 for percent, respcetively. According to Mac Nemar test, both thod presented statistical significance (p < 0,05). In order to find out the specificity, additional 70 serum samples from individuals with other parasitoses, such as cysticercosis (30), trichinosis (26) and fascioliasis (14) were also tested, IHAT presented a specificity of 92,7 for percent and for ELISA-IgG the specificity using a cut-off of average + 3 SD was 99,3 and 100,0 por percent with sera dilution of 1:100 and 1:500 respectively when a cut-off of average +2 SD was considered, we found a specificity of 91,3 and 97,3 por percent, for 1:100 and 1:500 dilutions. The use of ELISA-IgG and purified antigen in the diagnosis of human hydatidosis is discussed