PURPOSE: Malignancy is a common and important cause of exudative pleural effusions. Because pleural fluid cytology and pleural biopsy specimens do not provide a diagnosis in a high percentage of malignant effusions, several tumor markers have been studied. To overcome this limitation, we hypothesized that measurement of procalcitonin and C-reactive protein (CRP) would be useful in differentiating between trasudates and exudates and besides between benign and malignant effusion.
METHODS: We studied prospectively 178 consecutive patients with pleural effusion (malignant 57, tuberculous 51, parapneumonic 31, empyema 5, miscellaneous benign 7, transudative 27). We examined standard parameters of pleural effusion and measured serum and pleural procalcitonin using immunoluminometric assay. CRP in serum and pleural fluid was determined by turbidimetric immunoassay.
RESULTS: Pleural procalcitonin levels in exudate are significantly higher than those in transudate, 0.81±3.09 ng/mL and 0.12±0.12 ng/mL, respectively (p = 0.007). Pleural CRP levels are significantly elevated in exudate compared with transudate, 2.83±3.31 mg/dL and 0.74±0.67 mg/dL, respectively (p < 0.001). Pleural procalcitonin levels in benign effusion are significantly higher than those in malignant effusion, 1.15±3.82 ng/mL and 0.25±0.92 ng/mL, respectively (p = 0.032). Pleural CRP levels are significantly elevated in benign effusion compared with malignant effusion, 3.68±3.78 mg/dL and 1.42±1.54 mg/dL, respectively (p < 0.001). Pleural procalcitonin levels in non-tuberculous effusion are significantly higher than those in tuberculous effusion, 1.16±3.75 ng/mL and 0.13±0.37 ng/mL, respectively (p = 0.008).
CONCLUSION: Taken together, we conclude that the measurement of the level of procalcitonin and CRP in pleural fluid is helpful in differentiating between transudates and exudates. Moreover it is useful in differentiation between benign and malignant pleural effusions.
CLINICAL IMPLICATIONS: The measurement of the procalcitonin and CRP levels at the onset of pleural effusion may facilitate the differentiation of the cause of pleural effusions.
DISCLOSURE: Sang-Ha Kim, No Financial Disclosure Information; No Product/Research Disclosure Information