[Diagnostic value of serum and pleural fluid adenosine deaminase activity in tuberculous pleurisy]

The biological diagnosis of tuberculous pleurisy poses the problem of the time required to obtain results and of the sensitivity of the usual diagnostic methods. The determination of adenosine deaminase (ADA) activity has been proposed for the diagnosis of tuberculous pleural effusion and for the follow-up. In the present study, ADA in pleural effusion (p-ADA) and in serum (s-ADA) has been measured in 2 groups of patients: tuberculosis (27) and non-tuberculosis (53) patients. The upper limit of the normal values was fixed at 37 U/L. Comparing these 2 groups, we observed a specificity of 81.2% and a sensitivity of 66.6%. The PPV and the NPV were respectively 64.3% and 82.7%. We used p-ADA/s-ADA ratio for diagnosis of tuberculous pleural effusion, a threshold value of 1.8 gave a sensitivity of 82.6% and a specificity of 84.8%. Within the tuberculosis patient group, the activity of ADA decreased after the appropriate treatment initiation. Thus, the determination of ADA activity and/ or the p-ADA/s-ADA ratio, can help to recognize the tuberculosis origin of pleural effusions.