Verification of Roche reference ranges for serum prolactin in children, adolescents, adults, and the elderly

Reference intervals (RIs) for prolactin are of high clinical importance for diagnosis, treatment, and prognosis of hypothalamic-pituitary disorders. The aim of this study was to verify the Roche reference ranges for serum prolactin in children, adolescents, adults, and the elderly. : An indirect method based on currently laboratory data was used on the reference ranges. Nine thousand one hundred and thirteen prolactin results were included. Pregnancy, lactation, exercise and reported pathologies were ruled out and only samples were collected between 8AM and 12PM were used. Reference ranges with a confidence interval of 95% (95% CI) were estimated. : Compared to the manufacturer's reference values and for the corresponding age group, the median values obtained in our study were 10 – 60% higher depending on the age and sex of the patients. Elevated levels of serum prolactin were observed in the neonatal period and values decrease until median values near 200 mUI/L in childhood. During the children's period, no gender differences were observed for prolactin level. The gender difference in prolactin levels became significant from pre-adolescence until the age of 60. Prolactin levels increased significantly (p<0.001) between children and young adults, followed by a gradual and continuous decrease until young senior age.: The prolactin reference values proposed by the manufacturer in the data sheet appeared unsuitable. Laboratories should review reference ranges, and a partitioning with sex and different age groups may be appropriate.