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fractional excretion of urea
Defined as: excreted urea/filtered urea
Indications:
- evaluation of prerenal azotemia in patients on diuretics
Procedure:
Measured as:
(urine urea/serum urea) / (urine creatinine/serum creatinine)
Clinical significance:
- useful for assessing prerenal azotemia in patients with FENA > 1% & on a diuretic (FENA can be elevated by diuretics)
- fractional excretion of urea is less influenzed by diuretics than FENA
- a value of < 35% for fractional excretion of urea is consistent with prerenal azotemia
Related
fractional excretion of sodium (FENA)
urea (carbamide)
General
urinary indices
References
- Medical Knowledge Self Assessment Program (MKSAP) 16, 17.
American College of Physicians, Philadelphia 2012, 2015
- Gotfried J, Wiesen J, Raina R, Nally JV Jr.
Finding the cause of acute kidney injury: which index of
fractional excretion is better?
Cleve Clin J Med. 2012 Feb;79(2):121-6. Review.
PMID: 22301562 Free Article