Serum and Pleural Fluid Procalcitonin for Discriminating Complicated Non-Purulent from Uncomplicated Parapneumonic Effusions

Objective: In parapneumonic effusions (PPE), tube thoracostomy is indicated in complicated parapneumonic effusions (CPPE) and empyema. This study focused on assessing the value of procalcitonin (PCT) in serum and pleural fluid for the identification of patients with PPE that ultimately require chest tube drainage. Methods: A retrospective clinical study was performed with two different patient groups. A total of thirty patients with PPE were included: twelve of these patients had CPPE, and eighteen had uncomplicated parapneumonic effusions (UPPE). Serum and pleural fluid PCT concentrations were evaluated before treatment. Three classical parameters (pH, glucose and LDH) in the pleural fluid were also assessed. Results: Serum and pleural fluid PCT concentrations were statistically different between CPPE and UPPE groups (P=0.002 and P=0.006, respectively). A positive and significant correlation was detected between serum and pleural fluid PCT levels (r=0.72, P=0.000). Diagnostic specificity and sensitivity values for serum and pleural fluid PCT in discriminating CPPE from UPPE were 61% and 92%, and 71% and 83% at the 0.26 and 0.50 ng/mL cut-off values, respectively. Conclusion: Serum and pleural PCT in patients with PPE were significantly different between the CPPE and UPPE. They may both contribute to the identification of CPPE with at least better sensitivity than the use of pH, glucose, or lactate dehydrogenase, but the accuracy of PCT should be further investigated.