FGF23 and acute kidney injury: Among patients with AKI, FGF-23 levels were higher in nonsurvivors (n = 4) compared with survivors (n = 8), with respective median levels of 4446 RU/mL (IQR, 3455-5443) versus 544 RU/mL (IQR, 390-1948; p = 0.02).