Blood biomarkers to improve bacteremia diagnostics in Emergency Department pediatric patients
Background: Bacteremia and sepsis is the leading cause of death in children worldwide. Early recognition and timely treatment are essential for preventing progression to more severe forms and lethal outcomes. CRP and Complete Blood Count (CBC) are initially preferred tests to distinguish between bacterial and viral infections. Specific early markers are still missing.
Aim: We aimed to investigate the diagnostic value of NLR (neutrophil-lymphocyte ratio), PLR (platelet-lymphocyte ratio) and MPV (mean platelet volume) for differentiation between bacterial and viral infections. Moreover, applying cut-off levels of inflammatory markers we aimed to develop a prediction model to distinguish between severe bacterial infection and viral infection.
Methods. Children (n=115) presented with fever to emergency department (ED) were retrospectively enrolled into study and divided into two groups: sepsis/bacteremia (n=68) and viral infection (n=47) patients. Children with chronic diseases, immunodeficiency or cancer, late arrival (>48 hours) to ED or recent antibiotic therapy were not enrolled. Sepsis/bacteremia has been proven by typical clinical symptoms and positive blood culture. Viral infection group was composed of clear acute upper respiratory tract viral infection cases. For all study participants blood has been drawn and CBC as well as inflammatory markers such as C-reactive protein (CRP) level were assessed at the presentation. Additionally, NLR and PLR have been calculated. Data analysis was performed using Microsoft Excel and SPSS Statistics version 21.0. P value of <0.05 was considered significant.
Results. There was no significant difference in children age or gender between sepsis/bacteremia and viral infection groups (9 [3?24] months vs. 12 [6?27] months, p = 0.274 for age; 31 (45.6%) vs. 23 (48.9%), p = 0.857 for gender). Not surprisingly, sepsis/bacteremia participants demonstrated significantly higher white blood cells (WBC) (17.94 ± 10.04 × 109/l vs. 10.42 ± 4.21 × 109/l, p < 0.001) and neutrophils count (10.93 ± 8.03 × 109/l vs. 5.08 ± 3.42 × 109/l, p < 0.001), as well as CRP level (88.92 ± 83.05 mg/l vs. 13.95 ± 16.06 mg/l, p < 0.001). Moreover, sepsis/bacteremia patients had relevant increase in absolute platelets count (370.15 ± 134.65 × 109/l vs. 288.91 ± 107.14 × 109/l, p = 0.001) and NLR (2.69 ± 2.03 vs. 1.83 ± 1.70, p = 0.006). NLR and MPV were significantly lower in infants (≤ 12 months) of viral infection group when they arrived at the ED late (>12 hours) after the onset of symptoms compared with sepsis/bacteremia group (1.16 ± 1.06 vs. 1.90 ± 1.25, p = 0.025 for NLR and 8.94 ± 0.95 fl vs. 9.44 vs. 0.85 fl, p = 0.046 for MPV). Of the other inflammatory biomarkers, NLR with a calculated threshold of 1.58 showed sensitivity and specificity of 73% and 58%, respectively, and an area under the curve (AUC) of 0.75 (95% CI, 0.65 to 0.84) for NLR to identify children with sepsis/bacteremia.
Conclusion: NLR and MPV could be used in clinical practice and allow distinguishing between bacterial and viral diseases and predict bacteremia among infants up to 1 year but only if arrived later than 12 hours.
