MedFrontier Intact FGF23 Assay Kit

Intact fibroblast growth factor 23 (FGF-23) is a phosphaturic hormone primarily secreted by osteocytes and osteoblasts in bone, playing a central role in phosphate and vitamin D metabolism. Functioning through its interaction with FGF receptors and the co-receptor Klotho, intact FGF-23 reduces renal phosphate reabsorption and suppresses 1α-hydroxylase activity, thereby lowering serum phosphate levels and active vitamin D (calcitriol) synthesis. The “intact” form of FGF-23 refers specifically to the biologically active, full-length peptide, which is distinguished from its inactive C-terminal fragments that may accumulate in some disease states. Measurement of intact FGF-23 in serum or plasma is typically performed using ELISA assays designed to detect only the full-length molecule, offering a more accurate reflection of its physiological function and clinical relevance.

In both research and clinical contexts, intact FGF-23 serves as a critical biomarker for disorders of mineral metabolism, particularly in chronic kidney disease (CKD). In CKD patients, elevated intact FGF-23 levels are among the earliest detectable changes in mineral dysregulation and are predictive of adverse outcomes such as cardiovascular events, left ventricular hypertrophy, and mortality, even before hyperphosphatemia develops. It is also used in the diagnosis of rare hypophosphatemic disorders such as tumor-induced osteomalacia and X-linked hypophosphatemia, where inappropriately high intact FGF-23 levels contribute to chronic phosphate wasting and impaired bone mineralization. In research, monitoring intact FGF-23 levels provides insight into the pathophysiology of mineral bone disorders, guides the development of targeted therapies, and helps evaluate the efficacy of treatments such as phosphate binders, calcimimetics, or FGF-23 antagonists. Its unique role at the intersection of bone, kidney, and cardiovascular systems underscores its value as a multifaceted biomarker across disciplines.

This product is manufactured in Japan by Canon Medical Diagnostics.