Community acquired pneumonia (CAP) is common in childhood. To improve the management of CAP, we must develop better diagnostic methods to detect the marker which could be used both to assess the severity of CAP and determine the risk of complications. Biomarkers, preferably in combination with clinical risk scores, are increasingly used to identify specific patients at risk, to judge the severity of illness and prognosis of CAP and more recently to guide of therapy. As the allocation of resources is, however, important, the high prices for the use of newly developed biomarkers make their use less attractive. Recently, the use of the ratio between neutrophil and lymphocyte in diagnosing the severity of infectious diseases is becoming widely acceptable. Initially, this so-called neutrophil-lymphocyte ratio (NLR) was studied as an infection marker in ICU patients and found to correlate well with disease severity and outcome, according to APACHE-II and SOFA scores

Objectives of our research was to investigate the usefulness of NLR as biomarker of bacterial community-acquired pneumonia severity in a group of children.

Methods: a retrospective study was conducted in a tertiary care pediatric hospital in Ternopil. Data of patients were analyzed. Clinical characteristics, complications and outcomes were related to the NLR. In the course of the work, it was found that NLR is associated with the severity of systemic inflammation in paediatric patients with CAP. Admission NLR has good diagnostic value in the prediction of the severity and outcome of CAP with a higher prognostic accuracy as compared with traditional infection markers.