Enzyme linked protein-A: an ELISA for detection of IgG antibodies against Mycobacterium tuberculosis in intestinal tuberculosis.

Summary Enzyme linked protein-A has been used to develop an enzyme-linked immunosorbant assay (ELISA) to detect circulating IgG antibodies to Mycobacterium tuberculosis . The specific binding of protein-A to IgG fractions through Fc receptors, makes the test more specific for detection of total IgG antibodies. The ELISA system has been used for detection of circulating antibodies to M. tuberculosis H 37 Ra in 22 patients with histologically proven intestinal tuberculosis and 88 healthy controls, in addition to 7 diseased controls. The ELISA has been found to be a sensitive test as it was positive in all 22 patients with intestinal tuberculosis. Its specificity was 85 % in Indian controls and 97 % in Norwegian controls. The test is easy to perform and may be recommended for the serological diagnosis of intestinal tuberculosis.