<prompt> True about acute tubular necrosis -Urine specific gravity 1.020Urine osmolality 300 mosmoleskgUrine Na 1OmeqLBlood urea nitrogen :plasma creatinine ratio 20  <response>: . A blood urea nitrogen BUNcreatinine ratio BCR 20 0.081 in international unit is used to distinguish pre-renal azotemia PRA and acute tubular necrosis ATN. However, there is little evidence that BCR can distinguish between these two conditions andor is clinically useful. Ref Harrison20th edition pg 278 