Markers for bacterial infection in children with fever without source.

Objectives: To compare the diagnostic properties of procalcitonin (PCT), C reactive protein (CRP), total white blood cells count (WBC), absolute neutrophil count (ANC) and clinical evaluation to detect serious bacterial infection (SBI) in children with fever without source.

Design: Prospective cohort study.

Setting: Paediatric emergency department of a tertiary care hospital.

Participants: Children aged 1-36 months with fever and no identified source of infection.

Intervention: Complete blood count, blood culture, urine analysis and culture. PCT and CRP were also measured and SBI probability evaluated clinically with a visual analogue scale before disclosing tests results. Outcome measure Area under the curves (AUC) of the receiver operating characteristic curves.

Results: Among the 328 children included in the study, 54 (16%) were diagnosed with an SBI: 48 urinary tract infections, 4 pneumonias, 1 meningitis and 1 bacteraemia. The AUC were similar for PCT (0.82; 95% CI 0.77 to 0.86), CRP (0.88; 95% CI 0.84 to 0.91), WBC (0.81; 95% CI 0.76 to 0.85) and ANC (0.80; 95% CI 0.75 to 0.84). The only statistically significant difference was between CRP and ANC (Δ AUC 0.08; 95% CI 0.01 to 0.16). It is important to note that all the surrogate markers were statistically superior to the clinical evaluation that had an AUC of only 0.59 (95% CI 0.54 to 0.65).

Conclusion: The study data demonstrate that CRP, PCT, WBC and ANC had almost similar diagnostic properties and were superior to clinical evaluation in predicting SBI in children aged 1 month to 3 years.