Plasma procalcitonin and C-reactive protein in acute septic shock: clinical and biological correlates

Crit Care Med. 2002 Apr;30(4):757-62. doi: 10.1097/00003246-200204000-00006.


Objective: To determine the relationship between plasma procalcitonin (PCT) levels, C-reactive protein (CRP), white blood cell count (WBC), ionized calcium (Ca2+), and patient outcome; and to compare the diagnostic and prognostic information provided by PCT and by CRP.

Design: Prospective, observational study.

Setting: Intensive care unit.

Patients: Fifty-three patients with septic shock, consecutively diagnosed according to consensus guidelines.

Interventions: None.

Measurements and main results: Blood was sampled at diagnosis and 24 and 48 hrs later and in a subgroup (n = 23) after 120 hrs. PCT was measured with LUMItest and CRP with Vitros slides. Ca2+ was calculated according to McLean-Hastings from calcium and protein levels on Vitros. In all 53 patients, PCT and CRP were elevated (>0.5 ng/mL and >10 mg/L, respectively) within 24 hrs after diagnosis. Nonsurvivors (n = 25) were older (p <.001) and had higher Acute Physiology and Chronic Health Evaluation (APACHE) II scores (p =.02) at diagnosis but did not differ in sepsis etiology, medical history, sex ratio, levels of PCT, CRP, and Ca2+, or WBC count at any time point. Using logistic regression, initial PCT levels were correlated with CRP values (p =.001) and APACHE II score (p <.05), but not with age, gender, Ca2+ levels, survival, or type of pathogen. Within 48 hrs, however, PCT levels decreased more frequently from baseline in survivors than in nonsurvivors (80% vs. 41%, p <.05). Likewise, CRP levels decreased more often in survivors (100% vs. 64%, p <.05) but only at 120 hrs.

Conclusions: PCT levels were correlated with the severity of disease at onset (APACHE II) and inflammation (CRP) but not with Ca2+ levels. Inaugural PCT or CRP levels per se poorly predicted outcome but decreasing levels were associated with a higher probability of survival. In this respect, PCT was found to be an earlier marker than CRP.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Disease
  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Biomarkers / blood
  • C-Reactive Protein / analysis*
  • Calcitonin / blood*
  • Calcitonin Gene-Related Peptide
  • Calcium / blood
  • Female
  • Humans
  • Intensive Care Units
  • Leukocyte Count
  • Male
  • Middle Aged
  • Prognosis
  • Prospective Studies
  • Protein Precursors / blood*
  • Shock, Septic / blood*
  • Shock, Septic / mortality


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