BUN and Creatinine on the NCLEX
Renal function markers, BUN/Cr ratio, eGFR.
BUN and creatinine assess kidney function. Ratio tells pre-renal vs intrinsic.
Normal
BUN 7-20. Creatinine 0.6-1.2 (varies by sex, muscle mass).
BUN/Cr ratio
>20:1, pre-renal (dehydration, GI bleed, HF, low effective volume). ~10-15:1, intrinsic renal disease.
eGFR
Calculated. >90 normal. <60 chronic if persistent.
BUN elevators besides kidney
GI bleed (protein digestion), steroids, dehydration, high-protein diet, catabolism.
Frequently asked
Creatinine in elderly?
Lower muscle mass means even mild creatinine elevation can signal real dysfunction. Trust eGFR.
Trend or single value?
Trend. Single creatinine alone less actionable.
Quick check
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