Diagnostic Significance of Adenosine Deaminase and Lymphocytes in Suspected Tuberculous Pleural Effusion

Abstract

CONTEXT: Tuberculosis is a major public health problem in India. Tuberculous pleural effusion is a paucibacillary manifestation of the Tuberculosis, so isolation of Mycobacterium tuberculosis is difficult, biomarkers being an alternative for diagnosis. Pleural fluid Adenosine deaminase (ADA) level is being used in diagnosis of Tubercular pleural effusion. The combination of ADA and pleural fluid lymphocyte count is being recognized as a better method for increasing the specificity of ADA test. The present study was conducted to analyze the diagnostic usefulness ofAIM: ADA alone (≥ 40U/L) compared with the combination of ADA and pleural fluid lymphocyte count ( ≥ 50% ). SETTINGS AND DESIGN: METHODS AND MATERIAL:Retrospective study. Study was conducted for a period of one year from May 2017 to April 2018. A total of 110 pleural fluid samples data was analysed. SPSS 20STATISTICAL ANALYSIS USED: statistical software. ADA level in Tuberculous pleural effusion ranged from 40U/L to 112U/L with mean value ofRESULTS: 69.4U/L. Sensitivity, Specificity, Positive predictive valve (PPV) and Negative predictive values (NPV) for ADA alone were 93.2%, 76.4%, 82% and 90.6% respectively. For ADA and lymphocyte count the Specificity and PPV increased (98% and 98.1% respectively) with hardly any decrease in sensitivity or NPV (89.8% and 89.5% respectively). CONCLUSION: Combined use of ADA and pleural fluid lymphocyte count increases the specificity and PPV when compared to the specificity of ADA test alone in diagnosing Tubercular pleural effusion.