Sepsis is an extremely common systemic condition in the Emergency Room (ER), which is found to be to be one of the leading causes of death among patients accessing the ER. To date, the diagnosis of sepsis does not rely on any specific markers for infectious conditions, but several methods of assessing the general condition of the patient, namely markers that elevate in a variety of inflammatory conditions (PCR, PCT), indices of tissue hypoxia (serum lactate), and scores based on the haemochromocytometric examination, the markers of function of different organs, and vital parameters expressed by the patient at the time of assessment (SOFA, qSOFA, SIRS, NEWS). These markers, in addition to not be specific for sepsis, have an insufficiently early peak of presentation to readily identify all patients presenting with this condition. Presepsin, as the N-terminal portion of the soluble component of Cluster of Differentiation 14 (CD14), is elevated almost exclusively in infectious conditions; moreover, its elevation in infectious contexts is extremely early compared with that of markers already in use, allowing early identification of septic patients who to date would be recognized as such only hours after the onset of the septic process. In addition, the determination of this biomarker could make it possible to stratify patients by prognosis, allowing greater attention to be paid to the most severe patients. It is hypothesized that the Presepsin assay in emergency room will allow to increase the rapidity and specificity of sepsis diagnosis compared with the diagnostic procedure currently used, improving the outcomes of patients accessing the emergency room with symptoms suggestive of sepsis. The main purpose of the present study is to evaluate the role of serum assay of presepsin in the early diagnosis of sepsis in patients presenting to the emergency department with clinical suspicion of sepsis by comparing the values obtained with traditionally used such as PCR, PCT, and blood culture. The secondary objective is to evaluate presepsin as a prognostic biomarker and useful for mortality risk stratification of the same patients, comparing the values obtained with validated predictor scores of mortality and/or severity (APACHEII, SOFA, qSOFA).