A Combinatorial Biomarker for Infection Diagnosis in Children

To describe the epidemiology, clinical presentation, diagnosis, therapy, and treatment outcomes of patients in whom the combination biomarker BV (combination of TRAIL, IP-10, and CRP) is used, and to compare them with control patients without BV measurement. Secondary objectives: * Qualitative evaluation of indication as well as adherence to the test result. * Comparison of antimicrobial therapy, performed diagnostics, hospitalization, and outcomes between patients with high BV score (bacterial) and patients with low BV score (viral).