Diagnostic Value of Adenosine Deaminase Activity in Tuberculous Pleursy

In this study, we measured pleural fluid and serum adenosine deaminase (ADA) activity in 89 patients with pleural of and 15 healthy person choosen as control group. Patients were divided into four groups; 1) Tuberculosis (n=24), 2) Malignancies (n=27), 3) Pneumonias (n=28),4)Congestive hearth failure (CHF) (n=10). Mean ADA activity of tuberculous effusions (54.88 ± 5.77 U/1) was significantly higher than those of malignant, pneumonic effusions and transudative effusions in CHF. With the cutoff level of 40 Ul I, we found that the sensitivity and the specifity of pleural fluid ADA activity (PADA) in discriminating between tuberculous and other effusions were 71% and 91%, respectively. Mean pleural fluid to serum ADA ratio (PIS ADA) in tuberculous pleurisy was higher than that in any other group. Pleural fluid to serum ADA ratio exceeding 2_5 appeared to have sensitivity of 88% and specifity of 72%. ADA to protein, ADA to LDH, ADA to cholesterol, and ADA to total bilirubine ratios of pleural fluids were also determined and found that the mean values in tuberculosis are all higher than those of other effusions. They also showed the sensitivity and the specifity comparable to those found in PADA and PIS ADA. It seems that these parameters can be used in establishing tuberculous pleural effusion as well as PADA and PIS ADA.