Insulin-like growth factor (IGF-1) is belived to play a key role in regulation of cell activity. IGF-1 levels are greatly influenced by various factors, chronologic age, and sex. The aim of our study was to evaluate age-defined normative serum values in the pediatric population in children younger than 2 years of age. A total of 87 otherwise healthy children (47 male, 36 female) aged 0 to 2 years were enrolled. Serum IGF-1 determinations were performed by the IRMA method. Mean IGF-1 serum levels for boys younger than 1 year of age were 113 ng/ml, SD 45 ng/ml, and for girls 75 ng/ml, SD 45 ng/ml. In the group of children younger than 2 year of age, mean IGF-1 levels for boys were 110 ng/ml, SD 50 ng/ml, and for girls 122 ng/ml, SD 66 ng/ml. Conclusion: Serum concentrations of IGF-1 in children younger than 2 years are promising as a means for monitoring of the response in young children, and may be a supplementary aid in describing individual changes in various diseases.

        Key words: insulin-like growth factor-1, age-defined normative values, age 0 to 2 years