Normative Basal Values of Hormones and Proteins of Gonadal and Adrenal Functions from Birth to Adulthood

In clinical practice, it is fundamental to compare the results of hormonal examinations obtained in the laboratory with reliable reference values. This is particularly difficult when faced with rare conditions, such as disorders of sex development, where not routinely assayed peptide hormones as well as intermediate steroid metabolites are often needed and local reliable reference values are not available. There are considerable differences among techniques and assays used in clinical and research laboratories. In fact, laboratory hormonology is undergoing a critical transition between techniques for quantitative determination: established immunoassays and mass spectrometry. Harmonizing results from different laboratories is a major challenge along the path leading to the establishment of consensus reference intervals for steroid hormones. Most of the efforts are being concentrated on testosterone, with very encouraging results being provided by the harmonization of liquid chromatography-tandem mass spectrometry results. However, this goal is still far from being achieved for the other steroid and small-molecule hormones, and a much more challenging perspective is foreseeable for protein hormones. In addition to technical issues, the importance of the definition and of the characterization of the reference population as well as sampling and processing methodology should not be underestimated, as these aspects may impact on hormonal axis and compound stability. The aim of the present review is to provide a comprehensive overview of the circulating reference values in basal condition of the hormones and proteins involved in sex development reported to date in the peer-reviewed literature. We present a series of tables where we have collected the reference intervals for each specific hormone and protein.