Investigation of the clinical and epidemiological characteristics of patients between 1 month and 18 years of age with elevated procalcitonin

Kaya, E. Investigation of the Clinical and Epidemiological Characteristics of Patients Between 1 Month and 18 Years of Age with Elevated Procalcitonin. Eskişehir Osmangazi University, Faculty of Medicine, Department of Pediatrics, Eskişehir, 2025. The aim of this study was to evaluate the changes in PCT levels over time, their relationship with age and gender, underlying diseases, diagnosis distribution, and infectious agents in pediatric patients aged 1 month to 18 years with elevated procalcitonin (PCT). This retrospective study analyzed procalcitonin values measured on days 0, 1, and 3, as well as clinical and laboratory data, in pediatric patients within the specified age range. Patients were classified according to gender, age group, underlying disease, preliminary diagnosis, definitive diagnosis, and infection site, and the obtained data were statistically analyzed. The majority of PCT requests (71.9%) were made by the pediatric intensive care unit, followed by the hematology-oncology unit (12.1%), the pediatric unit (9.3%), the infant unit (4.2%), and the pediatric infectious diseases unit (2.5%). A dynamic change was observed in PCT levels measured by day, with the mean being 9.48±23.4 ng/mL on day 0, 14.99±32.32 ng/mL on day 1, and 10.50±23.2 ng/mL on day 3. The increase between day 0 and day 1 and day 3, and the decrease between day 1 and day 3, were found to be statistically significant (p<0.05). No significant effect of age and gender on PCT levels was observed. In terms of underlying diseases, the most common were neurological diseases, malignancy, and metabolic diseases, while pneumonia, sepsis, bronchiolitis, and malignancy were prominent among pre-diagnoses. PCT levels were particularly elevated in association with these diagnoses. Regarding infectious agents, respiratory tract pathogens predominate, with viral agents (Rhinovirus/Enterovirus, Respiratory Syncytial Virus, Adenovirus) and some bacterial agents (E. coli, Klebsiella pneumoniae, Pseudomonas aeruginosa) detected. Our study demonstrates that procalcitonin levels are a valuable biomarker for dynamically monitoring infection and assessing treatment response in children. Furthermore, its ability to be used independently of age and gender makes PCT a practical and reliable parameter in the pediatric population.