Interpretation of BUN and serum creatinine. An interactive exercise.

1. Serum creatinine is the true assessment tool of renal function. 2. BUN and serum creatinine are best interpreted together, comparing the two results. 3. Normal BUN is 10 to 20 mg/100 mL and serum creatinine is 0.6 to 1.2 mg/100 mL. 4. An extrarenal problem produces a BUN to serum creatinine ratio of greater than 25:1. 5. Renal failure (acute or chronic) produces a BUN to serum creatinine ratio of 10:1. 6. Renal failure and extrarenal problems can co-exist.