Plasma urea / creatinine ratio of 20:1 may be seen in :

Answer is c (Pre-renal failure) Plasmaurea / creatinine ratio of 20:1 is characteristic of prerenal ARF Rhabdomyolysis and chronic glomerulonephritis are causes of Intrinsic ARF and are associated with a plasma urea / creatinine ratio of < 10-15. Ureteric calculi are associated with post-renal ARF