Raised Pleural Adenosine Deaminase: Does it Mean Tuberculosis?

Abstract

We read with interest, the article by Valdes et al 1. Valdes L. San Jose E. Alvarez D. Sarandeses A. Pose A. Chomon B. et al. Diagnosis of tuberculous pleurisy using the biologic parameters adenosine deaminase, lysozyme, and interferon gamma. Chest. 1993; 103: 458-465 Abstract Full Text Full Text PDF PubMed Scopus (193) Google Scholar who conclude that raised pleural adenosine deaminase (PADA) and interferon (IFN) are both useful for early diagnosis of tuberculous pleural effusions (note that determining PADA is much less expensive). Since its initial description by Piras et al, 2. Piras M.A. Gakis C. Budroni M. Andreoni G. Adenosine deaminase activity in pleural effusions: an aid to differential diagnosis. Br Med J. 1978; ii: 1751-1752 Crossref Scopus (166) Google Scholar raised PADA has been assumed as a great/useful diagnostic tool for tuberculous pleurisy. But some of the works from the continents conclude that PADA has poor diagnostic value in tubercular pleural effusion. 3. Van Keimpema A.R. Slaats E.H. Wagenaar J.P. Adenosine deaminase activity, not diagnostic for tuberculous pleurisy. Eur J Respir Dis. 1987; 71: 15-18 PubMed Google Scholar , 4. Maartens G. Bateman E.D. Tuberculous pleural effusions: increased culture yield with bedside innoculation of pleural fluid and poor diagnostic value of adenosine deaminase. Thorax. 1991; 46: 96-99 Crossref PubMed Scopus (86) Google Scholar The methods of adenosine deaminase (ADA) activity estimation are either colorimetry or spectrophotometry, following the enzymesubstrate reaction. It may be one of the reasons why the cut off points for significant ADA activity has been described variously as that of 25 U/L, 2. Piras M.A. Gakis C. Budroni M. Andreoni G. Adenosine deaminase activity in pleural effusions: an aid to differential diagnosis. Br Med J. 1978; ii: 1751-1752 Crossref Scopus (166) Google Scholar 30 U/L, 5. Prasad R. Tripathi R.P. Mukerji P.K. Singh M. Srivastava V.M.L. Adenosine deaminase activity in pleural fluid: a diagnostic test of tuberculous pleural effusion. Indian J Chest Dis Allied Sci. 1992; 34: 123-126 PubMed Google Scholar 45 U/L, 6. Ocana I. Martinez-Vazquez J.M. Segura R.M. Fernandez de Sevilla T. Capdevilla J.A. Adenosine deaminase in pleural fluids: test for diagnosis of tuberculous pleural effusion. Chest. 1983; 84: 51-53 Crossref PubMed Scopus (202) Google Scholar 47 U/L, 1. Valdes L. San Jose E. Alvarez D. Sarandeses A. Pose A. Chomon B. et al. Diagnosis of tuberculous pleurisy using the biologic parameters adenosine deaminase, lysozyme, and interferon gamma. Chest. 1993; 103: 458-465 Abstract Full Text Full Text PDF PubMed Scopus (193) Google Scholar 50 U/L. 7. Nagraj M.V. Ashokan P.K. Hande H.M. Adenosine deaminase in pleural effusions. J Assoc Physicians India. 1992; 40: 157-159 PubMed Google Scholar Besides the ambiguity of significant PADA level, raised PADA has also been reported in pleural effusions due to rheumatoid arthritis, lymphoma, lung cancer, and mesothelioma, and it has been aptly quoted in a recent editorial. 8. Shah A. Tuberculous pleural effusions: a diagnostic problem [editorial]. Indian J Chest Dis Allied Sci. 1992; 34: 115-116 PubMed Google Scholar Besides the above conditions, increased PADA activity has been recorded in effusions associated with spontaneous pneumothorax and also parapneumonic effusions. 4. Maartens G. Bateman E.D. Tuberculous pleural effusions: increased culture yield with bedside innoculation of pleural fluid and poor diagnostic value of adenosine deaminase. Thorax. 1991; 46: 96-99 Crossref PubMed Scopus (86) Google Scholar All the above facts point to the fact that raised PADA is unlikely to be a useful diagnostic aid (definitely not confirmatory) for tuberculous effusion; however, sufficiently raised PADA may be an aid to differential diagnosis and should be taken into cognizance along with other clinical and laboratory parameters.