Diagnostic Significance Of Interferon Gamma Concentration, Adenosinase Deaminase Activity In Tuberculous And Nontuberculous Pleural Effusions

Objective: To assess the clinical usefulness of interferon-gamma and adenosine deaminase in differentiating diagnosis of tuberculous pleural effusion from nontuberculous pleural effusions.Methods: A prospective study was carried out from July 2002 to April 2004 .During this period, 88 consecutive patients presenting with pleural effusions were included in the study. 46 patients with tuberculous pleural effusions ,25 patients with malignant pleural effusions and 17 patients with pleural effusions due to other causes were studied. 30 cases of control group were also studied . The IFN-γconcentration and ADA activity in all specimens were determined by ELISA and enzyme kinetic analytical method respectively. Analysis was made by using sensitivity and specificity, and the best cutoff point was determined by the receiver operating characteristic (ROC) curve.Results: The IFN-γconcentration in the tuberculous pleural effusion group was 497.13±200.79pg/ml, which was significantly higher than that in the malignant group(72.16±78.58pg/ml, p<0.001). A cutoff of 120.69 pg/ml yielded a sensitivity of 84.78% , a specificity of 88.10% , an accuracy of 86.36% ,a positive predictive value of 88.64% and a negative predictive value of 84.09% for the diagnosis of tuberculous effusions. The ADA level (54.45±15.33 U/L) in the tuberculous pleural effusion group was significantly higher than that in the malignant group (18.67±16.54 U/L, p<0.001).With a cutoff of 39.30 U/L, the sensitivity, specificity , accuracy, positive predictive value and negative predictive value were 89.13%, 80.95% , 85.23%,83.67% and 87.18% respectively. The parallel test gave a sensitivity of 98.35% and a negative...