The diagnostic efficacy of adenosine deaminase in tubercular effusion

This study aims to evaluate the diagnostic efficacy of adenosine deaminase in tubercular effusions.

This study was conducted at the Department of General Medicine and Cardiovascular and Thoracic Surgery, SKIMS, for a period of two years between November 2008 and November 2010. A total of 57 patients presenting with pleural effusions during the two-year study period, who presented with clinical manifestations suggestive of tuberculosis (i.e., the presence of productive cough, low-grade fever, night sweats, weight loss, and chest pain, especially if these symptoms last (3)4 weeks) were included in the study. If the patients presented with less than two of these symptoms, and especially if the clinical manifestations were of <4 weeks duration, they were excluded from the study.

The mean adenosine deaminase activity level in all the 57 patients was 109 U/L while the mean adenosine deaminase activity levels in pleural TB patients was 80 U/, and 64 U/L in the controls (p=0.381). Considering 40 U/L as the cut off, the results were positive in 35 out of 39 tuberculosis patients and 9 out of 18 controls. The sensitivity of adenosine deaminase for tubercular effusions worked out to be 90%, with only 50% specificity.

This study suggests that the estimation of adenosine deaminase activity in pleural fluid is a rapid diagnostic tool for differentiation of tubercular and non tubercular-effusions. The sensitivity and specificity of adenosine deaminase for tubercular effusions in this study was 90% and 50% respectively.