Pleural Fluid CA-125 in Patients with Pleural Effusion

Background: Primary and secondary infections and malignancies are inflammatory causes of fluid accumulation in the pleural space. TB is one of the infective causes of pleural effusion and is similar to malignancies because of its subacute and chronic process; although their management is extremely different. CA-125 is a glycoprotein tumor marker with molecular weight of 200 KD, which is found on the surface of ovarian and some normal and inflammatory cells. In both malignancy and tuberculosis, this tumor marker increases in serum and consequently in pleural fluid. This study was conducted to evaluate and compare CA-125 tumor marker in pleural effusion resulting from malignancies and tuberculosis. Materials and Methods: twenty-seven TB patients (18 men and 9 women), with the mean (±SD) age of 37.3±13.9 yrs. and 23 patients affected by malignant tumors (16 men and 7 women) with the mean (±SD) age of 57.9±17.7 yrs. were evaluated during 2004-2005. In malignant cases, diagnosis was made through microscopic inspection of the biopsy samples and cytology of pleural fluid. For recognition of tuberculosis, culture and smear of sputum or gastric lavage, biopsy of pleura and pleural fluid and PCR methods were used. Pleural fluid samples were collected and the amount of their CA-125 was measured by CLIA method. The cut-off value of CA-125 was obtained from a ROC curve. Results: The mean (±SD) level of CA-125 in pleural fluid was 159.1±214, and 2149.2±4513.6 U/ml in tuberculosis and malignancies, respectively; which showed a statistically significant difference between the two groups (p <0.01). Conclusion: CA-125 marker levels in pleural effusion may be used as a diagnostic index for differentiation of TB and malignancy induced pleural effusions. (Tanaffos 2005; 4(16):23-27) Keywords: CA-125, Pleural effusion, Tuberculosis, Malignancy