The decreased serum urea nitrogen-creatinine ratio.

Sometimes, readily available laboratory data can provide valuable hidden information. Such is the case with the serum urea nitrogen-creatinine ratio. A normal ratio is 8:1 to 10:1. It is well known that an elevated ratio is seen in cases of prerenal or postrenal uremia. Less appreciated are the diagnostic possibilities suggested by a decreased serum urea nitrogen-creatinine ratio (ie, <8). Several clinical circumstances can lead to a decreased serum urea nitrogen-creatinine ratio.