True about pre-renal azotemia
High-Yield Explanation
In pre-renal azotemiaBUN/creatinine ratio above 20, FeNa<1%, hyaline casts in urine sediment,urine specific gravity >1.018, urine osmolality >500 mOsm/kgPigmented "muddy brown" granular casts and tubular epithelial cell casts are seen in acute tubular necrosis.Ref: Harrison's 19e pg: 1805