A potential role for D-dimer in the diagnosis of tuberculous pleural effusion.

BACKGROUND AND OBJECTIVES Tuberculous pleural effusion (TPE) is associated with enhanced local fibrinolysis; however, its role in TPE has not been studied. The present study aims to investigate whether pleural D-dimer, a fibrinolysis marker, plays a diagnostic role for TPE. PATIENTS AND METHODS Patients with pleural effusion were recruited prospectively. All subjects underwent a standard thoracocentesis and pleural effusion samples were collected. The diagnosis of pleural effusion was based on clinical, radiological, bacteriological, and histopathological examinations. Pleural D-dimer levels were measured by immunonephelometry assay. The capacity of pleural D-dimer to differentiate TPE from non-TPE was assessed with receiver operating characteristic curve analyses. RESULTS A total of 87 patients with pleural effusion were included in the study (32 TPE cases and 55 non-TPE controls). Subjects with TPE showed a marked elevation of pleural D-dimer than those with other etiologies (1082.66±453.83 vs. 319.98±266.78 mg/L FEU, p < 0.05). The area under curve when pleural D-dimer was used to differentiate TPE from non-TPE was 0.928 (95% confidence interval: 0.878-979). With a cut-off value of 622.5 mg/L FEU, the sensitivity and specificity were 84.38% and 85.45%, respectively. CONCLUSIONS Pleural D-dimer levels are higher in TPE than other causes of pleural effusions. D-dimer might be useful as a simple, surrogate marker for TPE. Further studies are needed to confirm our findings.