Introduction One of the major advantage of procalcitonin compared to other parameters is its highly and early increase in response to bacterial infection. The increased procalcitonin levels can be observed 3 to 6 hours after infectious challenge. It is a parameter that made a significant contribution to the clinical diagnosis, severity of infection and in the same time procalcitonin kinetics cand be used to assess the effectiveness of treatment.

Methods A single- centre observational study consecutively enrolled 70 preschool children with lower respiratory tract infections who were hospitalised in Paediatric Clinic Hospital of Sibiu between January 2013 and January 2017. Procalcitonin, were measured on admission, after 48–72 hours and after 24–48 hours without fever.

Results The majority of hospitalised children were male (64,7%) coming from urban areas (70,58%) aged between 3 and 4 years (76,47%). Criteria for antibiotherapy were: fever, the value of procalcitonin above 2 ng/mL, the increase of other inflammatory markers and modified chest radiography (interstitial pneumonia, bronchopneumonia). Procalcitonin serum decreased on average after five days of antibiotic treatment and most children required hospitalisation lasting between 5 and 10 days (58, 82%). Only 17% of cases had complications, like pleurezia and they required a longer length of hospital stay.

Conclusion Procalcitonin allows the fast identification in children who need antibiotics. This study allows a more individualised approach for each patient, a shorter use of antibiotics and a shorter stay in the hospital.