Diagnosis of pulmonary tuberculosis: Evaluation of the TB IgA EIA assay in Morroco

We analysed 2 evaluation lots of the TB IgA EIA test in pulmonary tuberculosis patients (TBp). Sera were obtained from 345 TBp, 18 healthy subjects (HS), 28 subjects in contact with tuberculous patients (CS) and 16 non-tuberculous lung disease patients (N-TB) for the first evaluation lots and 302 TBp, 60 HS, 21 CS and 18 N-TB for the second. IgA titres against p-90 antigen with the second evaluation lot were significantly higher than the first evaluation lot. With the second evaluation lots, the sensitivity was 78.8% whereas with the first evaluation lot, the sensitivity was 75.9%. Specificity for the first and second evaluation lots was 50% and 70.7% respectively. The sensitivity of this test is still not satisfactory to establish pulmonary tuberculosis diagnosis.