Honda H, et al. - Researchers determined the influence of iron administration on serum fibroblast growth factor 23 (FGF23) levels in 123 hemodialysis (HD) patients. Of overall patients treated with erythropoiesis-stimulating agents, once-weekly intravenous iron was received by 22 patients and daily oral iron with iron-containing phosphate binders was received by 17 patients. From participants, blood samples were drawn prior to each HD session, at baseline and on days 3, 5, 7, and 14, and using these samples, intact FGF23 and biomarkers of iron metabolism were assessed. Findings revealed that in HD patients, intact FGF23 levels may be influenced by intravenous iron administration, independently of phosphate and iron metabolism.