To find out a sensitive and specific marker for early diagnosis of tubercular pleural effusion, this cross sectional study was carried out in the of National Institute of Diseases of the Chest and Hospital (NIDCH), Dhaka. One hundred and three pleural effusion cases were enrolled in the study. Out of the 103 cases, 62 were tubercular pleural effusion cases and 49 were nontubercular cases. Among the nontubercular cases, 30 cases were due to malignancy, 8 were due to pneumonia and rest 3 cases were due to nephrotic syndrome, congestive cardiac failure and rheumatoid arthritis. Considering 40 U/L as a cut off value for ADA level, the test result was positive in 58 out of 62 patients of tuberculosis indicating sensitivity of the test as 94%; however, among 41 non-tuberculous patients, 5 presented ADA activity level more than 40U/L, which lowers the specificity of the test to 88%. ADA levels were significantly higher in tuberculous than in nontuberculous cases (p value <0.001). It may be concluded that ADA levels are significantly high in patients with tuberculous pleural effusion compared to that in non-tubercular group. Sensitivity (94%) and specificity (88%) of the test in tuberculous pleural effusions are very high, when cut off value set at 40U/L. The result indicated that the analysis of ADA levels in pleural effusion constitute a very useful marker for the diagnosis of tubercular pleural effusion (TPE) which, in addition, can be made quickly in a noninvasive way. DOI: http://dx.doi.org/10.3329/bjmb.v6i2.17642 Bangladesh J Med Biochem 2013; 6(2): 40-48

Background: Tuberculosis is a leading cause of worldwide preventable morbidity and mortality from an infectious agent. A defi nite diagnosis of tubercular pleural effusion can be diffi cult to make because of low sensitivity and/or specifi city of noninvasive traditional diagnostic tools. This study is done to fi nd out a sensitive and specifi c marker for early diagnosis of tuberculous pleural effusion. Materials and Methods:One hundred and three pleural effusion cases were enrolled in the study, out of which 62 were tuberculous pleural effusion cases and 49 were non-tuberculous cases.Results: Considering 40 U/L as a cut off value for Adenosine deaminase assay level, the test result was positive in 58 out of 62 patients of tuberculosis indicating sensitivity of the test as 94%; however, among 41 non-tuberculous patients, 5 presented ADA activity level more than 40U/L, which lowers the specifi city of the test to 88%. ADA levels were signifi cantly higher in tuberculous than in non tuberculous cases (P value <0.001). Conclusion:It may be concluded that ADA levels are signifi cantly high in patients with tuberculous pleural effusion compared to that in non tuberculous group. Sensitivity (94%) and specifi city (88%) of the test in tuberculous pleural effusions are very high, when cut off value set at 40U/L. The result indicated that the analysis of ADA levels in pleural effusion constitute a very useful marker for the diagnosis of TPE which, in addition, can be made quickly in a non-invasive way.