Neutrophil-to-lymphocyte ratio in adult patients with bacteremia at the Emergency Service

Relación neutrófilos-linfocitos en bacteriemia en pacientes adultos que ingresan al Servicio de Urgencias

Objective: To determine the diagnostic value of increased levels of the neutrophil-tolymphocyte ratio (NLR) in patients admitted to the emergency service with bacteremia.
Materials and methods: One-hundred-four patients were included, of which 81 were eligible and were compared with patients with negative blood cultures in a 1:1 relationship. Receiving operating characteristic (ROC) curves were constructed and the sensitivity, specificity, predictive values and probability indicators for the absolute leukocyte count (ALC) and neutrophil absolute count (NAC), CRP and NLR were determined.
Results: The only infection markers with an area under the curve (AUC) >0.7 were CRP and NLR. The cutoff value for NLR in bacteremia was 13.2 with an AUC of 0.71; which provided a sensitivity of 63%, and a specificity of 71.6%; positive predictive value (PPV) of 69% and negative predictive value (NPV) of 66%. The cutoff value for CRP in bacteremia was 17.1 with an AUC of 0.73; which provided a sensitivity of 66% and a specificity of 74.7%; PPV of 73% and NPV of 69%. A statistically significant difference was found in patients mean age 68± 17.1 years with positive blood cultures vs patients mean age 58 ± 21.1 years with negative blood cultures (p=0.001). The average number of patients with a GFR <60 ml/min/1.73m2 in the positive bacteremia group was 69.1% compared with the negative bacteremia group 46.9%, (p=0.0042).
Conclusion: Increased values of NLR in patients admitted to the emergency service are a reliable and accessible predictor in bacteremia.

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