Setting: Department of Paediatrics in a University Hospital.
Objective: To evaluate ABC-ELISA as serodiagnostic tests for tuberculosis in children.
Design: An avidin-biotin-peroxidase conjugated anti-human immunoglobulin (ABC) enzyme-linked immunosorbent assay (ELISA) was established to measure serum immunoglobulin G (IgG) antibodies to polymerized old tuberculin (OT), tuberculin purified protein derivative (PPD) and the 30,000 dalton (30 kDa) native antigen of Mycobacterium tuberculosis, in 122 tuberculosis patients and 187 healthy children.
Results: In those patients who had received less than 3 months of chemotherapy the sensitivities of the tests based on OT, PPD and the 30 kDa antigen were 40.3%, 50.0% and 36.1% respectively; the positive predictive values were 92.6%, 94.7% and 93.8% respectively and the negative predictive values were 58.6%, 62.9% and 57.2% respectively.
Conclusion: The ABC-ELISA may be useful for the diagnosis of pulmonary and extrapulmonary tuberculosis in groups of children with a high prior probability of tuberculosis. Antibodies to the 30 kDa antigen persisted longer than did those to OT and PPD.