Diagnostic and prognostic values of pleural fluid procalcitonin in parapneumonic pleural effusions

Chest. 2009 Jul;136(1):205-211. doi: 10.1378/chest.08-1134. Epub 2009 Mar 2.


Background: The role of procalcitonin (PCT) in parapneumonic pleural effusion (PPPE) as a diagnostic and prognostic biomarker of the outcome has not been examined before.

Methods: From the emergency department, 82 adult patients with pleural effusions were enrolled in this prospective study and divided into the following two groups: the PPPE group (n = 45); and the non-PPPE group (n = 37). Levels of pleural fluid (PF) PCT and serum (S) PCT were determined in all patients after study enrollment as well as on day 3 only in the PPPE group by a newly developed time-resolved, amplified, cryptate emission assay.

Results: Both PF-PCT and S-PCT levels were significantly higher in the PPPE group than the non-PPPE group (p = 0.01 and 0.0003, respectively). S-PCT had a better diagnostic performance than PF-PCT, with an area under the curve of the receiver operating characteristic of 0.834 for S-PCT and 0.752 for PF-PCT (p = 0.006). In the PPPE group, both PF-PCT and S-PCT levels on days 1 and 3 were significantly higher in patients who were in high-severity risk classes (all p values < 0.05). Day 3 PF-PCT/S-PCT ratios were significantly lower in patients who needed chest tube drainage for > 7.5 days (corrected p = 0.02).

Conclusion: S-PCT has higher diagnostic accuracy than PF-PCT in differentiating PPPEs from non-PPPEs. However, both PF-PCT and S-PCT are useful in the severity assessment of patients with PPPEs. The PF-PCT/S-PCT ratio may help to predict prolonged chest tube drainage.

Publication types

  • Controlled Clinical Trial

MeSH terms

  • Aged
  • Biomarkers / metabolism
  • Calcitonin / metabolism*
  • Calcitonin Gene-Related Peptide
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Pleural Effusion / diagnosis*
  • Pleural Effusion / metabolism*
  • Pleural Effusion / therapy
  • Pneumonia / diagnosis*
  • Pneumonia / metabolism*
  • Pneumonia / therapy
  • Predictive Value of Tests
  • Prognosis
  • Prospective Studies
  • Protein Precursors / metabolism*
  • ROC Curve
  • Reproducibility of Results
  • Severity of Illness Index


  • Biomarkers
  • CALCA protein, human
  • Protein Precursors
  • Calcitonin
  • Calcitonin Gene-Related Peptide