The diagnosis of
sepsis is often difficult and belated, substantially increasing mortality in affected patients. Its early identification allows for us to choose the most appropriate
therapies in the shortest time, improving patients' outcomes and eventually their survival. Since neutrophil activation is an
indicator of an early innate immune response, the aim of the study was to evaluate the role of Neutrophil-Reactive Intensity (NEUT-RI), which is an
indicator of their metabolic activity, in the diagnosis of
sepsis. Data from 96 patients consecutively admitted to the Intensive Care Unit (ICU) were retrospectively analyzed (46 patients with and 50 without
sepsis). Patients with
sepsis were further divided between
sepsis and
septic shock according to the severity of the illness. Patients were subsequently classified according to renal function. For the diagnosis of
sepsis, NEUT-RI showed an AUC of >0.80 and a better negative predictive value than
Procalcitonin (PCT) and
C-reactive protein (CRP) (87.4% vs. 83.9% and 86.6%, p = 0.038). Unlike PCT and CRP, NEUT-RI did not show a significant difference within the "septic" group between patients with normal renal function and those with
renal failure (p = 0.739). Similar results were observed among the "non-septic" group (p = 0.182). The increase in NEUT-RI values could be useful in the early ruling-out of
sepsis, and it does not appear to be influenced by
renal failure. However, NEUT-RI has not proved to be efficient in discriminating the severity of
sepsis at the time of admission. Larger, prospective studies are needed to confirm these results.