Antituberculosis antibodies were detected in 164 children and adolescents who had tuberculosis and who were infected with mycobacteria. The diagnostic value of indirect hamagglutination tests with phosphatide antigen and tuberculin, complement uptake, passive hemolysis, and enzyme immunoassay for evaluating the progression of tuberculosis was defined in patients at a specialized sanatorium. The significance of the tests increases when they are concurrently used.