Can the delta neutrophil index differentiate bacterial infection without bacteremia from viral infection in pediatric febrile patients?

Introduction: The delta neutrophil index (DNI) is a reported marker that can be used to predict the diagnosis, prognosis, and disease severity of bacteremia and sepsis. We determined whether the DNI is useful in differentiating bacterial infection without bacteremia from viral infections in pediatric febrile patients in the emergency department (ED). Method: This study involved a retrospective analysis of patient medical records from the pediatric ED of the teaching hospital. After extracting the list of patients with complete blood count (CBC) and DNI data,patients with bacterial infection (BI) without bacteremia and those with viral infection (VI) were identified. The primary outcome was the diagnostic performance of DNI in differentiating BI without bacteremia from VI. The secondary outcome was a comparison of the diagnostic performances of DNI, CRP, WBC, and neutrophil count between the two groups. Results: After excluding 756 patients, a total of 574 patients were included in the study. A total of 151 (26.3%) patients were in the BI group, and 423 (73.7%) were in the VI group. There was no significant difference in DNI between the two groups (3.07 (2.52~3.63) vs. 3.51 (2.40~4.62), mean (95% CI), BI vs. VI). There was no difference in WBC count, neutrophil levels, or RDW between the two groups, but CRP levels were significantly higher in the BI group than in the VI group (1.39 (1.19~1.60) vs. 4.56 (3.66~5.45), mean (95% CI), VI vs. BI, p < 0.05). The AUROCs achieved in analyses of DNI, WBC count, neutrophil levels, RDW, and CRP levels were 0.5016, 0.5531, 0.5631, 0.5131, and 0.7389, respectively, and only CRP levels were helpful in differentiating BI from VI. Conclusion: In the absence of bacteremia, DNI wound not be helpful in differentiating BI from VI in pediatric febrile patients.