Both BUN
and creatinine are metabolic waste products,
and the healthy kidneys keep them range at a normal level. If kidneys can’t play their job optimally, excess creatinine and blood urea nitrogen will build up in the body. Clinically, 5.0mg/dl of creatinine and 60mg/dl of BUN are two indicators of renal failure. To prevent so high BUN and creatinine level, the best method is to control them as soon as you find them just higher than the normal (9-20mg/dl for BUN, 0.5-1.2mg/dl for creatinine).