결핵성 흉막삼출액에서 흉수 Adenosine Deaminase치와 림프구/호중구 비의 진단적 유용성

Abstract

Background : The measurement of adenosine deaminase(ADA) level in pleural fluid is useful in the diagnosis of tuberculous(TB) pleural effusion. However, ADA is also elevated in other diseases such as malignancy, bacterial infections, empyema, and collagen vascular disease, ADA alone has limited value. The object of this study is to determine diagnostic usefulness of the combined use of ADA value with lymphocyte/neutrophil ratio(L/N ratio) rather than the use of ADA alone. Method: We evaluated 198 patients(age=55.9±12.9, M/F=2.7:1) with pleural effusion who had admitted in Gyeongsang National University Hospital from Jan. 1999 to Dec. 2001. retrospectively. Patients were divided into four diagnostic groups: TB pleural effusion(n=91), parapneumonic effusion(n=65), malignant effusion(n=21), and transudative effusion(n=13). The ADA level, differential cell count, biochemistry, cytology, and microbiology of each diagnostic groups were evaluated The sensitivity, specificity, negative predictive value(npv), positive predictive value(ppv) and efficiency were calculated at each ADA values and combined ADA value with various L/N ratios. Results: The ADA level in TB pleural effusion was significantly higher than that of parapneumonic effusion, malignant pleural effusion, and transudative effusion(p<0.05). Sensitivity, specificity, ppv, npv and efficiency at ADA ≧50 IU/L in the diagnosis of TB pleural effusion were 89.0%, 82.2%, 81.0%, 89.8% and 85.5% respectively. When ADA;≧50 IU/L was combined with lymphccyte/neutrophil ratio≧0.75, sensitivity, specificity, ppv, npv, and efficiency were 83.5%, 96.3%, 95.0%, 87.9% and 90.5% respectively. Specificity, ppv and efficiency were increased with combination of ADA value and L/N ratio. Conclusion: Combination of ADA value and L/N ratio in pleural effusion is more useful than ADA value alone in the diagnosis of TB pleural effusion.