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 μg/L) (p < 0.0001) and in surgical (10.45 vs. 3.89 μg/L; p < 0.0001) patients. At the cutoff of 1 μg/L, the LR+ was 4.78, at the cutoff of 6 μg/L was 12.53, and at the cutoff of 10 μg/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.