IL6 and bacterial infectious disease: The preoperative values of PCT (normal serum value: <0.1 μg/L: no bacterial infection; >0.5 μg/L: systemic bacterial infection) and IL-6 (normal serum value: <3.3 ng/L) showed also low levels in all patients with a mean of 0.05 μg/L (95% CI: 0.04-0.05) and 2.23 ng/L (95% CI: −0.13–4.59), respectively.