You need to assess the WHOLE picture:
Creatinine - A waste product largely from muscle metabolism (breakdown). Concentration of creatinine in the Blood depends upon the amount of muscle that you have and the ability of your kidneys to excrete creatinine. High values, especially with high BUN levels, may indicate problems with the kidneys. Because of its insensitivity in detecting early renal failure, the creatinine clearance is significantly reduced before any rise in serum creatinine occurs. The renal impairment may be due to intrinsic renal lesions, decreased perfusion of the kidney, or obstruction of the lower urinary tract. Low values are generally not considered significant.
BUN (Blood Urea Nitrogen) - A waste product, derived from protein breakdown, produced in the liver and excreted by way of the kidneys. High values may mean that the kidneys are not working as well as they should. BUN is also elevated by Blood loss, dehydration, high protein diets and/or strenuous exercise which may temporarily and artificially raise levels. A low BUN level may be the result of liver disease, a low protein diet, pregnancy, or drinking an extreme amount of water. Normal BUN levels should be between eight and 23 milligrams per deciliter of Blood (mg/dL); normal creatinine levels should be between 0.7 and 1.3 mg/dL.
BUN/Creatinine Ratio - By comparing the BUN level in the Blood to the creatinine level, your physician can determine if a high BUN level is caused by kidney disease, dehydration, or by gastrointestinal bleeding. Usually >20:1 in prerenal and postrenal azotemia, and <12:1 in acute tubular necrosis. Other intrinsic renal disease characteristically produces a ratio between these values.
Please Scroll Down to See Forums Below 
