Adenosine deaminase in pleural effusions with special reference to tuberculous effusions

Aim: The aim of this study is to assess the usefulness of Adenosine deaminase levels of the pleural fluid in three different groups of patients and to confirm its usefulness in the diagnosis of tuberculous effusions. Materials and methods: 25 consecutive patients admitted with their first episode of pleural of were included in the study. The routine investigations were history, clinical examination. Diagnosis of tuberculosis was made based on pleural fluid analysis, chest radiography and histo pathological examination of pleural tissue. After the final diagnosis was established, the patients fell into 3 groups namely Group I: 18 patients of Tuberculous effusion. Group II: 5 patients of transudate effusion. Group III: 2 patients of Malignant effusion. The exudates were separated from, transudates by pleural fluid protein content of 3 grams or over. Results: Mean age of the patients in tuberculosis effusion was 27.3 years. While that of transudate effusion 42.4 years and that of malignancy 50.5 years. The male to female ratios of tuberculosis patients was 13:5 and that of transudate effusion was 3:2 and malignant effusion 1:1. Out of the 25 cases 18 had tuberculous pleural effusion (72% ). 5 Patients are of tansudate effusion (20%; 3 are due to congestive cardiac failure , 2 patients of cirrhosis of liver), 2 Patients had Malignant effusion(8%; I due to sq.cell carcinoma lung, 1 due to undifferentiated carcinoma of lung) . 50% of tuberculous effusions were on the left side and 50% to the right side. In transudate effusions 2 had right sided effusions, 3 had bilateral effusions. In malignant effusions one had effusion on the right side and one had effusion on the left. The A D A level in tuberculous effusions ranged from 281 U/L to 100 I U / L. 95% of patients had levels above 55 IU/L. Malignant effusions had a range from 30-35 IU/L. In transudates the A D A levels ranged from 23 to 31 I U/ L. The mean protein concentration of tuberculous effusions was 4.93 gm % and that of malignant effusions 4.5 gm %. In transudate effusions it was 1.9 gm %. The mean A D A concentration in pleural fluid was clearly much higher in tubercular effusions (66.5 IU/L) than in transudate (28.2 1U/L) and in malignant effusions 32.51U/L. Pleural fluids from all patients with tuberculosis showed lymphocytosis. Conclusion: Estimating ADA activity of the pleural fluid has the advantage of a high sensitivity and specificity, Hence, it is concluded that estimation of adenosine deaminase activity in pleural fluid is an easy and reliable method for diagnosing tuberculous pleural effusion.