<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>: Answer is C Urinary sodium concentration 40 meql Prerenal Azotemia Prerenal ARF is associated with a urinary sodium concentration 20 meq1. A urinary sodium concentration 40 meq 1 suggests intrinsic type of A RF. Differentiating features between Pre-renal and Intrinsic ARF Prerenal Azotemia is the most common form of ARF and is caused by renal hypoperfusion either from generalized hypovolemia or from altered renal hemodynamics resulting in hypoperfusion By definition Renal parenchymal tissue is not damaged in prerenal ARF and prerenal ARF is rapidly reversible upon correction of the primary hemodynamic abnormality Analysis of urine and blood biochemistry provides several useful Renal failure Indices to distinguish prerenal ARF from intrinsic ARF Ischemic Nephrotoxic ARF 