IL6 and bacterial infectious disease: First, this retrospective single center study only involved a small number of samples; second, we did not compare presepsin to other promising biomarkers of bacterial infection that have been recently proposed, such as PCT and IL-6; third, we did not consider the effect of cellular immunity status of the patients (such as patients under chemotherapy, steroids treatment, etc.)on presepsin level; and fourth, bacterial culture was not considered in the diagnosis of sepsis.