DIAGNOSTIC ACCURACY OF TUBERCULOSIS USING PLEURAL FLUID CYTOLOGY AS A SCREENING TOOL AND COMPARING IT WITH BIOCHEMICAL PARAMETER - ADENOSINE DEAMINASE

Abstract

Background: Tuberculous pleural effusion (TPE) frequently occurs as a result of extrapulmonary tuberculosis. Early diagnosis continues to be difficult because of the low bacillary content of pleural fluid. This research sought to assess the diagnostic precision of pleural fluid cytology as an initial screening method for tuberculous pleural effusion and to contrast it with adenosine deaminase (ADA) levels.

Methods: This prospective observational study assessed 120 patients who had exudative pleural effusion. Pleural fluid specimens were examined for cytological patterns, focusing on lymphocyte dominance and mesothelial cell quantity. ADA levels were assessed in every sample. The final identification of tuberculous pleural effusion was made using a comprehensive reference standard that included microbiological confirmation, HPE investigation of the pleural biopsy, and the reaction to anti-tubercular cure. Sensitivity, specificity, PPV, and NPV were determined for both cytological patterns and ADA measurements.

Results: Out of the 120 patients, 78 (65%) were identified as having TPE. The presence of lymphocytes predominating (>50%) along with a lesser count of mesothelial cells (<5%) in pleural fluid cytology demonstrated a sensitivity of 84.6% and a specificity of 73.8% for diagnosing TPE. ADA at a cut off of 40 U/L showed a sensitivity of 92.3% and a specificity of 88.1%. The integration of cytological criteria and ADA levels exceeding 40 U/L raised the specificity to 95.2%, achieving a positive predictive value of 96.7%, while sensitivity fell to 79.5%.

Conclusion: Cytology of pleural fluid acts as an effective preliminary screening method for TPE, exhibiting high sensitivity and moderate specificity. When paired with ADA levels, the precision of diagnosis greatly enhances. This integrated strategy facilitates swift and economical assessment of patients with suspected TPE, especially in resource-constrained environments where advanced diagnostic equipment might not be accessible.in resource-limited settings where more advanced diagnostic tools may be unavailable.