Usefulness of neutrophil-to-lymphocyte count ratio, procalcitonin, and interleukin-6 for severity assessment of bacterial sepsis

Abstract Objectives To explore the usefulness of neutrophil-to-lymphocyte count ratio (NLR), procalcitonin (PCT), and interleukin-6 (IL-6) for the severity assessment of bacterial sepsis. Methods This study enrolled 100 patients with bacterial sepsis (disease group) who presented to Jinhua Central Hospital between March 2022 and March 2023 and 90 healthy individuals (control group). The patients were categorized into sepsis (64 cases), severe sepsis (18 cases), and septic shock (18 cases) groups according to the disease severity. The groups were compared in terms of the NLR, PCT, and IL-6, as well as the usefulness of these parameters, both alone and in combination, for the severity assessment of bacterial sepsis. Results The NLR, PCT, and IL-6 levels were significantly different among the three groups, with increasing values corresponding with disease aggravation. The area under the curve (AUC) values of the combinations of NLR, PCT, and IL-6 levels were higher than those of single markers. The sensitivity and AUC value of the combination of PCT and IL-6 levels were the highest (0.87), with a similar AUC value of the combination of NLR, PCT, and IL-6 (0.865); however, the specificity was significantly improved with the latter (0.938 vs. 0.859). Conclusions NLR, PCT, and IL-6 levels are significantly increased in bacterial sepsis, and the combination of PCT, and IL-6 levels can improve the sensitivity of the evaluation ability for severe sepsis, and is more economical.