Procalcitonin, C-reactive protein and APACHE II score for risk evaluation in patients with severe pneumonia

Clin Microbiol Infect. 2002 Feb;8(2):93-100. doi: 10.1046/j.1469-0691.2002.00349.x.


Objective: Procalcitonin (PCT) is a peptide that is found elevated in patients with sepsis and severe infections. In healthy persons PCT serum levels are below 0.1 ng/mL. The aim of this study was to investigate the value of serum PCT determination for risk evaluation in patients with pneumonia.

Methods: We focused on the correlation of PCT with the clinical status of the patient and prognosis of the disease. In a prospective study, in a nonsurgical intensive care unit the following parameters were assessed regularly in 93 patients with documented pneumonia: C-reactive protein (CRP), white blood cell count (WBC), body temperature, PCT and Acute Physiology and Chronic Health Evaluation (APACHE) II score.

Results: At the onset of infection 50% of the patients had elevated PCT levels above 2 ng/mL. The model of multivariate analysis of all tested parameters on days 0-5 stratified for clinical outcome (change in clinical classification or death) showed local significance for APACHE II score only. None of the other parameters in this model serves as an isolated indicator for change of clinical status or death. An intra-individual change of body temperature or CRP was never significantly associated with a change in the clinical status of the patient.

Conclusion: Change in PCT on admission and at the end of the observation period significantly indicated a clinical change.

MeSH terms

  • Body Temperature
  • C-Reactive Protein / analysis*
  • Calcitonin / blood*
  • Calcitonin Gene-Related Peptide
  • Community-Acquired Infections / blood
  • Community-Acquired Infections / diagnosis
  • Cross Infection / blood
  • Cross Infection / diagnosis
  • Humans
  • Multivariate Analysis
  • Pneumonia, Bacterial / blood*
  • Pneumonia, Bacterial / diagnosis*
  • Prognosis
  • Prospective Studies
  • Protein Precursors / blood*
  • Risk Factors


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