Age- and sex-specific reference intervals for sex hormones in children in Wuhan: a cross-sectional study of 2,477 healthy children and adolescents.

Background: The standards for diagnosing, monitoring, and treating endocrine diseases in pediatric patients often rely on laboratory assessments of children's growth and differentiation markers, among which sex hormones are pivotal. Nonetheless, due to the rapid development during childhood and adolescence and the substantial physiological differences between children and adults, sex hormone levels undergo significant fluctuations. Unfortunately, few laboratories in China currently provide reliable reference intervals (RIs) for children's sex hormones. Hence, it is imperative to establish age-, sex-, and assay-RIs for sex hormones. In this study, age- and sex-specific pediatric RIs for estradiol (E2), follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), progesterone (PROG), and testosterone (TESTO) were established using a Mindray automatic chemiluminescence immunoassay analyzer (CL-6000i).

Methods: In this cross-sectional study, a total of 2,477 healthy children and adolescents from birth to 19 years were recruited in Wuhan Children's Hospital from September 2022 to August 2023, and serum samples were collected. Serum samples were analyzed on a Mindray analyzer (CL-6000i) for detection of sex hormones, including E2, FSH, LH, PRL, PROG, and TESTO. After sample analysis, age- and sex-specific differences were assessed. RIs were established according to guideline C28-A3 of the Clinical Laboratory Standards Institute (CLSI).

Results: We observed a complex pattern of changes in the concentrations of various hormones from the neonatal period through adolescence. Given the sex- and age-dependent variations in all sex hormones, we identified the need for establishing specific RIs for several subgroups to capture the fluctuations in hormone levels across this developmental spectrum. Notably, during the first month of life, significant variations were observed in all six hormones levels, necessitating further subdivisions within the first year. Additionally, age groups demonstrating nonsignificant differences in hormone concentrations were merged, resulting in different age subgroups for each of the six sex hormones.

Conclusions: We established specific pediatric RIs for sex hormones in both male and female children and adolescents, and also examined the age- and sex-specific differences, aligning them with medical literature, thereby facilitating the interpretation of patient results.