Pleural Effusion, Adenosine Deaminase (ada) and Lactate Dehydrogenase (ldh) Enzymes Level, Correlated with Cytological Evaluation

Background: Measurement of pleural fluid adenosine deaminase (ADA) and Lactate dehydrogenase (LDH) enzymes activity has gained increasing popularity as a diagnostic test for tuberculous and non-tuberculous pleuritis, especially in countries where the prevalence of TB is high. It carries a high sensitivity, inexpensive and easy. Objective: To demonstrate the diagnostic value of increased level of ADA and LDH in pleural effusion correlated with the cytological, biochemical and bacteriological assessment. Methods: seventy-five patients presented with pleural effusions were studied (53 males and 22 females) their mean age was 43.8 years. In all cases after the clinical assessment, evaluation of the pleural fluid was done and this included cytological exam with biochemical tests (adenosine deaminase "ADA" enzyme, lactate dehydrogenase "LDH", protein and glucose level) and bacteriological tests (Gram stain, and Ziehl-Neelsen stain). Results: From the clinical data and lab tests, patients were divided into six groups according to the etiology of pleural effusion. Most (32 patients) were tuberculous, malignant effusion13 patients, infection 10 cases, heart failure 8 cases, idiopathic effusion 6 cases and miscellaneous 6 cases. Significant difference was found in ADA level in different effusions (P<0.005). Highest value of ADA was in TB effusions (the mean was 76.6 u/l), compared to malignant effusions (the mean was 32.4 u/l) and less values in other effusions. LDH highest value was in malignant and TB effusions (mean 321.1 and 314u/l respectively). Conclusion: Increased ADA levels in TB effusions can be used to differentiate tuberculous from nontuberculous effusions. And high LDH levels were useful in confirmation malignant effusions.