Recently FGF-23 was discovered as 22th protein of fibroblast growth factor family. FGF-23 is produced as a 226 amino acid polypeptide which has a cleavage site and the flagmented peptides are recognized in serum with full length peptide. It is suggested that serum full length FGF-23 level may be useful as an indicater for severity of osteomalacia such as tumor-induced osteomalacia, X-linked hypophosphatemic rickets and autosomal-dominant hypophosphatemic rickets. FGF-23 is a new regulatory element for mineral metabolism. Number of tests; 96 tests