Are there standardized cutoff values for neutrophil-lymphocyte ratios in bacteremia or sepsis?

Bacteremia and sepsis are common causes of morbidity and mortality worldwide, with incorrect or delayed diagnoses being associated with increased mortality. New tests or markers that allow a more rapid and less costly detection of bacteremia and sepsis have been investigated. The aim of this study was to clarify the cutoff value of the neutrophillymphocyte ratio (NLR) according to procalcitonin (PCT) level in the decision-making processes for bacteremia and sepsis. In addition, other white blood cell subgroup parameters, which are assessed in all hospitals, for bacteremia and sepsis were explored. This retrospective study included 1,468 patients with suspected bacteremia and sepsis. Patients were grouped according to the following PCT criteria: levels <0.05 ng/ml (healthy group), 0.05-0.5 ng/ml (local infection group), 0.5-2 ng/ml (systemic infection group), 2-10 ng/ml (sepsis group), and >10 ng/ml (sepsis shock group). One important finding of this study, which will serve as a baseline to measure future progress, is the presence of many gaps in the information on pathogens that constitute a major health risk. In addition, clinical decisions are generally not coordinated, compromising the ability to assess and monitor a situation. This report represents the first study to determine the limits of the use of NLR in the diagnosis of infection or sepsis using a cutoff value of <5 when sufficient exclusion criteria are used.