Appraisal of the total blood lymphocyte proliferation assay as a diagnostic tool in screening for tuberculosis

The total blood lymphocyte proliferation assay (TLP) was evaluated as a screening test for infection with Mycobacterium tuberculosis and was compared with the tuberculin (Mantoux) skin test. The results of TLP assays performed on 33 patients with tuberculosis and 37 non-tuberculous subjects were compared with results of skin tests performed in the previous year. There was a high correlation between skin test responses and TLP responses to PPD which was statistically significant. The sensitivity, specificity and the predictive value of a positive test were also similar for the skin test and TLP test. These findings suggest that the TLP test is as effective in screening for M. tuberculosis infection as tuberculin skin testing. Future research leading to further simplification of the TLP method may lead to it replacing intradermal skin testing.