Abstract: | The microdot enzyme immunoassay (EIA) has been used for the determination of antibodies to M. tuberculosis protein fractions, crude antigenic preparations, PPD and old tuberculin in tuberculosis patients and healthy persons. Purified protein fractions have been found to possess the highest sensitivity and specificity in microdot EIA. The determination of antibodies to these fractions has permitted the differentiation of persons infected with M. tuberculosis from healthy ones. The use of M. tuberculosis protein fractions permits the determination of IgA and IgC in the sera of tuberculosis patients. |