Growth Hormone and Steroid Assays’ Problems in Childhood and Puberty

Abstract

Growth hormone (GH) and insulin-like growth factor-I (IGF-I) are the most important laboratory parameters used in the diagnosis of GH-related disorders in childhood and puberty. Problems of the immunoassays (IAs) for measuring GH and IGF-I, including lack of standardization, harmonization, and comparability, should be well understood and considered in the clinical assessment and interpretation. Application of liquid chromatography coupled to mass spectrometry (LC–MS) could overcome the limitations of IAs, but is still far from wide clinical use. One approach in diagnosing and management of GH deficiency relies solely on the measurement of IGF-I. The second, more traditional approach comprises a two-step testing of GH concentrations after pharmacologic stimulation. Abnormal concentration of steroids in children and adolescents is of great clinical importance for diagnosing a variety of disturbances, but modern IAs despite of their high capacity, speed, and automation do not meet the requirements for sensitivity and specificity and have unacceptable performance. LC–MS provides the highest possible reliability for steroid analysis and already becomes the preferred routine technique in many laboratories. Further significant advantages of LC–MS include relatively high throughput and the ability to perform panel steroid profiling with simultaneous measurement of precursors, active hormones, and metabolites in a single sample, thus amplifying enormously the informative value of laboratory results, with ultimate improvement of patient care.