Pre-renal Urinary sodium < 20 mmol/L Fractional excretion of sodium (FeNa) << 1% Osmolality > 500 mosmol/kg Urinary osmolality / Plasma osmolality > 1.5 i.e. high urinary creatinine and urea Acute Tubular Necrosis (ATN) Urinary sodium > 40 mmol/L FeNa > 1% Osmolality < 350 mosmol/kg Ur osm / Pl osm < 1.5 Common Reversible … Continue reading Acute Renal failure – working classification