Which differentiating prerenal azotemia with ATN features oring pre-renal azotemia -
The normal kidney can elaborate urine with a maximum concentration greater than 1,200 mOsm/kg in states of dehydration. A urinary osmolality (Uosm) greater than 500 mOsm/kg,, is highly suggestive of prerenal azotemia Ref Harrison20th edition pg ,299
Urine osmolality > 500 mosmol/kg
Sodium spot excretion < 10 ml/L
Plasma transferrin/Ig ratio
All the above
Kidney