Score for Differentiating Pleural Tuberculosis from Malignant Effusion

Differential diagnosis of lymphocytic pleural effusions between tuberculous (TBE) and malignant (ME) effusion is usually difficult in daily practice. Our aim was to develop a score to differentiate TBE from ME effusions. A cohort of 138 consecutive patients with pleural effusion was prospectively studied from May 2014 through June 2017. Glucose, lactate dehydrogenase (LDH), proteins, white cell count, lactic acid, and pH in the pleural fluid were measured. Pleural effusions other than lymphocytic, patients with a final diagnosis other than tuberculosis or malignancy, and patients who met Light's criteria for transudate were excluded. Eighty-two samples (47 TBE and 35 ME) were included in the analysis. Using logistic regression analysis and Wald test, we developed a score including age, glucose, proteins, and lactic acid. The receiver operating characteristic curve (ROC) for the score was determined, and the area under the curve (AUC) was calculated. A cutoff of eight points was required to achieve 93.5% sensitivity, 78% specificity, and a likelihood ratio of 4.26 to distinguish tuberculosis from malignant pleural effusion. The AUC of the score was 0.915 (95% CI = 0.82⁻0.96).