Prerenal versus Intrarenal
Finding
Prerenal
Intrinsic
BUN/Creatinine Ratio
> 20
10-20
FENa
< 1%
>2%
Urine Na (meq/L)
< 20
> 40
Specific Gravity
> 1.020
~ 1.01
Urine osmolality (mOsm/kg)
> 500
< 350
Sediment
normal
granular casts,
epithelial casts