Table 3.

Laboratory tests commonly used to help separate volume-responsive AKI from volume-unresponsive AKI and hepatorenal syndrome

Volume-Responsive AKIVolume-Unresponsive AKIHepatorenal Syndrome
Fractional excretion sodium (%)<1.0>2.0–3.0<1.0
Urine sodium (mEq/L)<10–20>20–30<10
Fractional excretion urea (%)<25<25<25
Urine to plasma creatinine ratio>40/L<20/L>40/L
  • Prior administration of diuretics or sodium-containing fluids and pre-existing CKD will affect these variables. Modified from references 9, 21, 25, and 26, with permission.