Application of bone turnover markers in skeletal and extra-skeletal conditions in children and adults

The assessment of bone health is challenging. It comprises bone histomorphometry, imaging techniques and laboratory parameters including bone turnover markers (BTMs). The latter are bone-derived products which can be measured in biological fluids, including blood and urine. Considering the disadvantages and limitations of imaging techniques, BTMs serve as an additional, non-invasive source of information about the metabolic activity of the entire skeleton. BTMs have found applications as research and clinical tools in a wide range of skeletal and extra-skeletal conditions, including diagnosis and treatment of osteoporosis. Unfortunately, their utility in routine clinical practice, especially in children, is still limited due to heterogenous methodo­logy, intra- and inter patient variability, and a paucity of accurate reference ranges and approved guidelines. Therefore, there is a need for standardized clinical trials on currently available and new BTMs.