DIAGNOSTIC ROLE OF ADENOSINE DEMINASE ACTIVITY IN LYMPHOCYTE RICH PLEURAL EFFUSION: A VALUABLE TUBERCULOSIS BIOMARKER

Abstract

Tuberculosis (TB) is a chronic bacterial infection caused by mycobacterium tuberculosis which remains in dormant state for years and reactivates only when the immune system weakens or fails. Robert Koch discovered mycobacterium tuberculosis in 1882.Tuberculosis that occurs after initial exposure to the bacteria is often referred to as primary TB and is common among children up to 4 years of age and among immune-compromised persons. If TB bacteria break through the scar tissue, it results in recurrence of the pneumonia and cause active disease, referred to as secondary TB which can spread to other parts of the body like kidneys, bone, joints, peritoneum, pericardium and lining of the brain and spinal cord (meninges).This study is a step in this direction in which we tried to find out the diagnostic role of ADA in lymphocyte rich pleural effusion. This study  was conducted in the department of  biochemistry, Subharti Medical College, Meerut (Uttar Pradesh) .108 patients were included in  the study', based on specialised diagnostic criteria patients were divided into two groups tubercular and non tubercular. The non-tubercular group was further divided into following sub groups: CHF, CRF, pneumonia, empyema, and malignancy, Light’s criteria was fulfilled in all the cases to confirm the pleural fluid as exudate. All the data were recorded & statistically analysed. Out of 108 patients confirmed pulmonary tuberculosis cases were 48 in Tubercular group. Out of these patients  The ADA levels were range from 5.1-27 U/L.in non tuberculous group (n=60), ADA level were ranges from 46.8-48 U/l and in tuberculous group 43.3-45.2 U/L respectively. Positive Predictive Value (ppv) and the Negative Predictive Value (npv) were calculated and  were 86.6% (at 95% CI: 83.41-89.11), 85.7% (at 95% CI: 82.13-88.97) respectively.Finally it is concluded from the present study that ADA estimation in the pleural fluid is a powerful tool in the differentiation of etiology of pleural effusion and so ADA estimation has a definite diagnostic role in lymphocyte rich pleural effusion & may be used as a routine investigation for the diagnosis of such patients.

Keywords: adenosine deaminase (ADA),tuberculosis,plueral effusion,lymphocytes