OBJECTIVETo evaluate the discrimination of serum procalcitonin (PCT) and interleukin-6 (IL-6) between patients with sepsis and non-infectious inflammatory response syndrome (SIRS) and the prediction power of clinical outcome.

METHODSA perspective study was performed in 27 patients with sepsis and 30 patients with non-infectious SIRS. The serum concentrations of PCT, IL-6, C-reactive protein (CRP), white blood cell count, percentage of neutrophil, absolute neutrophil count, and maximal body temperature were obtained less than 24 hours after clinical onset of sepsis or SIRS.

RESULTSThe serum levels of PCT and IL-6 and percentage of neutrophil were significantly higher in patients with sepsis than in those with non-infectious SIRS (PCT: 5.54 [1.20, 32.74] microg/L vs 0.77 [0.22, 3.90] microg/L, P=0.001; IL-6: 163.66 [33.60, 505.26] ng/L vs 37.72 [22.52, 110.78] ng/L, P=0.004; CRP [15.28 +/- 8.41] g/L vs [9.51 +/- 7.65] g/L, P=0.010; and percentage of neutrophil: 0.91 +/- 0.04 vs 0.88 +/- 0.04, P=0.010). Receiver operating characteristic curve showed that the power of PCT and IL-6 were the best of all above. There was significant correlation between serum PCT or IL-6 and the acute physiology and chronic health evaluation (APACHE II) or sepsis-related organ failure assessment (SOFA) scores, so was between serum PCT and the intensive care unit (ICU) length of stay.

CONCLUSIONSPCT and IL-6 are more reliable indicators to differentiate sepsis and non-infectious SIRS than the conventional inflammatory markers, and correlate with the disease severity. PCT levels are significantly correlated with ICU length of stay.