Insulin-like growth factor-1 (IGF-1) plays a role in the diagnosis and treatment of growth hormone access and deficiency. As the interpretation of IGF-1 much depends on age- and gender-specific reference limits, the standard deviation score (SDS) is proposed as an indirect measure of GH status. Various IGF-1 immunoassays are used by laboratories which often provide non-comparable results due to the inherently high biological variation of IGF-1, lack of assay standardisation, as well as analytical variation and shifts in test results caused by lot changes of IGF-1 reagents, and variations in locally adapted reference limits.
To assess the clinical impact of IGF-1 test results, we designed clinical case-based vignettes and surveyed adult and paediatric endocrinologists in Australia and New Zealand to gain insight into their clinical decision making and action based on IGF-1 results. The case scenarios were designed to assess the degree of variation in IGF-1 results around age and gender-specific reference limits that would potentially affect clinical decisions. This lecture will present the outcomes of this survey and highlight clinician’s opinion about the clinical use and utility of IGF-1 test results. Endocrinologists’ feedback assists laboratories in deriving clinically relevant acceptance criteria for the analytical performance of IGF-1 methods and provides valuable information to laboratories and the diagnostics industry on the needs for improved analytical and clinical performance of IGF-1 assays.