Diagnostic value of adenosine deaminase in tuberculous pleural effusion: a meta-analysis

Background Many studies have investigated the usefulness of adenosine deaminase activity (ADA) in pleural fluid for the early diagnosis of tuberculous pleurisy. To summarize the diagnostic characteristics of ADA we undertook a meta analysis using a summary receiver operating characteristic (SROC) curve method. Methods Data sources were MEDLINE (1966-1999), the Cochrane Library and bibliographies of review and original articles. Studies were included if the absolute numbers of true positive, false negative, true negative and false positive observations were available or could be derived from the data presented; gold standards were described explicitly; and the criteria for a positive ADA result were reported. We constructed an SROC curve based on these extracted data to estimate the test characteristics. Results Forty articles were available for analysis. The gold standards used were pleural biopsy histology, microbiological examination of pleural fluid, pleural biopsy and sputum and the patient's clinical course or combinations of these. The sensitivity of ADA reported in the articles ranged from 47.1% to 100% and the specificity from 50-0% to 100%. The summary measure of test characteristics derived from the SROC curve was 92.2% for both sensitivity and specificity. Conclusions The test performance of ADA in tuberculous pleural effusion is reasonably good. Measurement of pleural ADA is thus likely to be a useful diagnostic tool for tuberculous pleurisy.