Procalcitonin in the diagnosis of inflammation in intensive care units.

Objectives: To assess the effectiveness of different procalcitonin cutoff values to distinguish non-infected (negative+SIRS) from infected (sepsis+severe sepsis+septic shock) medical and surgical patients.

Design And Methods: PCT plasma concentration was measured using an automated chemiluminescence analyzer in 1013 samples collected in 103 patients within 24 h of admission in ICU and daily during the ICU stay. We compared PCT levels in medical and surgical patients. We also compared PCT plasma levels in non-infected versus infected patients and in SIRS versus infected patients both in medical and in surgical groups.

Results: Median values of PCT plasma concentrations were significantly higher in infected than in non-infected groups, both in medical (3.18 vs. 0.45 microg/L) (p<0.0001) and in surgical (10.45 vs. 3.89 microg/L; p<0.0001) patients. At the cutoff of 1 microg/L, the LR+ was 4.78, at the cutoff of 6 microg/L was 12.53, and at the cutoff of 10 microg/L was 18.4.

Conclusions: This study highlights the need of different PCT cutoff values in medical and surgical critically ill patients, not only at the ICU admission but also in the entire ICU stay.