TABLE 2.

Differential Diagnosis of Acute Renal Failure Using Urinary Indices in Neonates (N) and Children (C)

UosmoU/P UreaU/P CreatinineUNaU/P OsmoKFI
NCNCNCNCNCNC
Prerenal>400>500>1020>30>40<30<10>1.5>2<2.5<1
Renal<400<3503<10<20>60>60<1<1>2.5>2
Nonoliguric3005<40>50>500.5>1
Postrenal>3505<15>60>60±±
  • Uosmo = urinary osmolality (mOsm/kg); U/P Urea = urine-to-plasma urea ratio (mg/mg); U/P Creatinine = urine-to-plasma creatinine ratio (mg/mg); UNa = urinary sodium (mEq/L); U/P Osmo = urine-to-plasma osmolality ratio (mOsm/mOsm); KFI = kidney failure index, calculated as urine sodium divided by the ratio of urine creatinine to serum creatinine.

    From Chan JCM, Alon U, Oken DE. Clinical aspects of acute renal failure. In: Edelman CM, ed. Pediatric Kidney Disease. Boston, Mass: Little Brown & Company; 1992:1923–1941.