Which differentiating prerenal azotemia with ATN features favouring pre-renal
The normal 24-hour urine osmolality is, on average, 500-800 mOsmol/kg of water.
After 12-14 hours of fluid intake restriction, the urine osmolality should exceed 850 mOsmol/kg of water
Urine osmolality > 500 mosmol/kg
Sodium spot excretion < 10 ml/L
Plasma transferrin/Ig ratio
none