In Critically Ill Patients, Serum Procalcitonin Is More Useful in Differentiating between Sepsis and SIRS than CRP, Il-6, or LBP

Manou Batstra,Paul Herbrink,Iwan A Meynaar,Wouter Droog,Rolf Vreede

doi:10.1155/2011/594645

Abstract

We studied the usefulness of serum procalcitonin (PCT), interleukin-6 (IL-6), lipopolysaccharide binding protein (LBP) levels and C-reactive protein (CRP) levels, in differentiating between systemic inflammatory response syndrome (SIRS) and sepsis in critically ill patients. Methods. In this single centre prospective observational study we included all consecutive patients admitted with SIRS or sepsis to the ICU. Blood samples for measuring CRP, PCT, IL-6 and LBP were taken every day until ICU discharge. Results. A total of 76 patients were included, 32 with sepsis and 44 with SIRS. Patients with sepsis were sicker on admission and had a higher mortality. CRP, PCT, IL-6 and LBP levels were significantly higher in patients with sepsis as compared to SIRS. With PCT levels in the first 24 hours after ICU admission <2 ng/mL, sepsis was virtually excluded (negative predictive value 97%). With PCT >10 ng/mL, sepsis with bacterial infection was very likely (positive predictive value 88%). PCT was best at discriminating between SIRS and sepsis with the highest area under the ROC curve (0.95, 95% CI 0.90–0.99). Discussion. This study showed that PCT is more useful than LBP, CRP and IL-6 in differentiating sepsis from SIRS.

Highlights

Ill patients often present with the systemic inflammation syndrome (SIRS), and these patients are treated with supportive therapy [1]
The difference in PCT levels between sepsis and systemic inflammatory response syndrome (SIRS) patients is maintained at least until day 3 or 4. This single-centre prospective observational study showed that serum PCT levels are more valuable than serum C-reactive protein (CRP), lipopolysaccharide binding protein (LBP), and IL-6 levels in discriminating sepsis from SIRS in critically ill patients
If PCT levels in the first 24 hours after ICU admission are below 2 ng/mL, sepsis with bacterial infection is virtually excluded

Summary

Introduction

Ill patients often present with the systemic inflammation syndrome (SIRS), and these patients are treated with supportive therapy [1]. If SIRS is due to infection, the diagnosis is sepsis and supportive therapy alone is insufficient. In their meta-analysis of 33 studies including almost 4000 patients, Uzzan et al conclude that PCT is superior to CRP in differentiating between sepsis and SIRS and these authors favour the routine use of PCT to help differentiate between SIRS, and sepsis [7]. Tang et al review 18 studies including 2097 patients to conclude that PCT cannot reliably differentiate sepsis from other causes of SIRS and they argue against the routine use of PCT to aid in differentiating sepsis from SIRS [6]. Interleukin-6 (IL-6) is an important mediator of the acute phase reaction in response to inflammation in sepsis.

Methods

Results

Discussion

Conclusion