Reference ranges for serum S100B neuroprotein specific to infants under four months of age.

Minor head traumatisms are a common reason for consultation in paediatric emergency departments. The diagnosis of traumatic brain injuries involves performing a cranial computed tomography (CCT), associated with a risk of cancer due to the radiation. The serum S100B is an effective biomarker used to reduce reliance on CCT. While reference ranges have been determined, the limited number of cases regarding infants less than 4months of age has not allowed this biomarker to be used with this age group. Our study aimed to determine reference ranges for serum S100B based on a larger number of infants from birth to 4months of age.Three centres included infants coming to the hospital for whom blood samples were taken. These samples were analysed to determine the upper reference values based on the 95th percentile.135 samples were analysed. The upper reference value was 0.51μg/L for children aged 0 to 4months. There was no effect of the gender.This study provides serum S100B reference ranges based on the largest group of neurologically healthy 0 to 4-month-old infants analysed to date. Reliable reference values of S100B for children are now determined. It is the first step towards validation of thresholds for studies integrating S100B into a clinical decision rule for MHT in children.