Diagnosis of Chronic Chagas disease

During the chronic phase, diagnosis relies primarily on serologic tests to demonstrate antibodies to the parasite.

Commonly used T. cruzi serologic tests include enzyme-linked immunosorbent assays (ELISA) and indirect immunofluorescent antibody tests (IFA).

Available assays vary in sensitivity and specificity depending on the protocol and antigens. A single positive test is not sufficient to confirm the diagnosis.

The recommended approach is to perform two or more serologic tests based on different techniques or antigens. Positive results on at least two tests are required for confirmation of the diagnosis.

Blood being tested by ELISA. Photo courtesy of WHO/TDR/Crump Argentina, 1999.