<prompt> Pre-renal Azotemia is characterized by all of the following. Except -Fractional excretion of Na 1Urinary osmolality 500 mosmkgUrinary sodium concentration 40 meq1Reversible with replacement fluids  <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 Urinary Osmolality The normal kidney can elaborate urine with a maximum concentration greater than 1,200 mOsmkg in states of dehydration. A urinary osmolality Uosm greater than 500 mOsmkg,, is highly suggestive of prerenal azotemia And it is reversible with fluid replacement Ref Harrison20th edition pg 299 