FGF23 and hypophosphatemia: Hypophosphatemia is observed immediately after KTx in 50% of patients,caused by the reestablishment of the glomerular filtration function and by theelevated serum levels of PTH and FGF23, which lead to increased phosphaturia.Prolonged hypophosphatemia, serum P < 2.4 mg/dL, can lead to disturbances in bonemineralization.