Adenosine deaminase and interferon gamma measurements for the diagnosis of tuberculous pleurisy: a meta-analysis.

OBJECTIVE

As Mycobacterium tuberculosis isolation rates in tuberculous effusions are relatively low, several biochemical and immunological markers have been proposed to diagnose tuberculous pleurisy including adenosine deaminase (ADA) and interferon-gamma (IFN-gamma). Here we summarise the literature on ADA and IFN-gamma as predictors of tuberculous pleurisy.

METHODS

After a systematic review of English language studies, we used summary receiver operating characteristic curve (SROC) analysis to determine the cumulative diagnostic accuracy of both markers and Bayes' theorem to calculate post-test probability of disease in settings with different prevalences of tuberculous pleurisy, assessed and reported the quality of primary studies.

RESULTS

From 1978 to November 2000, studies containing sufficient data for the determination of both sensitivity and specificity were 31 on ADA, including 4738 patients, and 13 on IFN-gamma, including 1189 patients. SROC curve yielded a maximum joint sensitivity and specificity of 93% for ADA and 96% for IFN-gamma. In the setting of tuberculous effusion prevalence of 5%, 25% and 85%, post-test probability of a negative ADA test were 0.4%, 2.4% and 24%, and 0.22%, 1.2% and 17% for a negative IFN-gamma test.

CONCLUSION

With the caveat that limitations in the design of the studies summarised here may distort estimates of test performance, ADA and IFN-gamma appear to be reasonably accurate at detecting TB pleurisy.