Comparison of the diagnostic utility of ADA and CA125 in tuberculous effusion

Abstract

BackgroundPleural effusion can be due to various pleural infections like TB as well as neoplasia. CA125 is a tumor marker found on the surface of ovarian and other normal cells as pleural cells. CA125 has been found to increase in serum and hence pleural fluid of patients with pleural effusion due to malignancy as well as due to TB.This study was conducted to evaluate the utility of CA125 in the diagnosis of pleural effusion resulting from TB, malignancy and pneumonia as well as to evaluate and compare the diagnostic utility of CA125 and ADA in the diagnosis of TB effusion. Patients and methods20 patients with tuberculous effusion (group I), 20 patients with malignant effusion (group II) and 20 patients with parapneumonic effusions (group III) were evaluated for the levels of CA125 and ADA in their pleural fluid. In malignant cases, diagnosis was made through microscopic inspection of pleural biopsy samples and cytology of pleural fluid. For diagnosis of tuberculosis, Ziehl Neelsen sputum smear, pleural fluid smear and/ or culture. Parapneumonic effusions were confirmed by pleural fluid cell count and culture & sensitivity. ResultsThe mean±SD level of CA125 in pleural fluid was 41.732±20.744U/ml, 309.27±79.564U/ml and 7.040±5.601U/ml in tuberculous, malignant and parapneumonic effusions respectively; which showed a statistically significant difference between the three groups (p<0.01). Pleural fluid CA125 was significantly higher in group II than group I (P1=0.000), and group III (P3=0.000). Pleural fluid CA125 was significantly higher in group I than group III (P2=0.000). Pleural fluid ADA was significantly higher in group I than group II (P1=0.000) and group III (P2=0.000). For diagnosing TB, CA125 showed a sensitivity and specificity of 74.1%, 76.9%, respectively while ADA demonstrated a sensitivity and specificity of 75% and 75% respectively. ConclusionCA-125 levels in pleural fluid may be used for differentiation between TB, pneumonic, and malignancy-induced effusions.Also CA125 may be added to the diagnostic workup of pleural fluid for accurate diagnosis of TB effusion.