<prompt> Fractional excretion of sodium 1 is seen in -Pre renal azotemiaAcute tubular necrosisAcute ureteral obstructionInterstitial nephritis  <response>: The fractional excretion of filtered sodium FENa has been demonstrated to be a reliably discriminating test between prerenal azotemia and acute tubular necrosis. One paicular urinary index cannot be expected to reliably discriminate between prerenal azotemia and acute renal failure in all cases Prerenal azotemia Oliguria urine volume 500 mLday or anuria 100 mLday, high urine specific gravity 1.015, normal urinary sediment, and low urinary sodium 20 mEqL; fractional excretion of sodium 1 are seen Ref Harrison20th edition pg 267 