Felis ISSN 2398-2950
Blood biochemistry: urea
Synonym(s): Blood urea nitrogen, BUN
Contributor(s): Kathleen P Freeman
Overview
- Produced in liver from ammonia derived from tissue/dietary protein and excreted by kidneys.
- Important marker of kidney function Kidney: chronic kidney disease, protein metabolism and upper gastrointestinal tract hemorrhage.
Sampling
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Tests
Methodologies
- Typically measured as (total) blood urea nitrogen (BUN). (Based on nitrogen portion of urea.)
- Blood urea is based on the entire molecule of urea.
- Blood strips can be used to get rapid results. Do not give precise reading but will show if levels are significantly elevated.
Availability
Validity
Sensitivity
- Low sensitivity in detection of renal dysfunction. Renal mass must be reduced by approximately 75% before BUN values are consistently outside of reference interval.
Specificity
- Low specificity for detection of renal dysfunction.
Technique (intrinsic) limitations
- Only significant in conjunction with other laboratory and clinical findings.
Most useful to assess in conjunction with a urine specific gravity Urinalysis: specific gravity.
Result Data
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Further Reading
Publications
Refereed papers
Other sources of information
- Ettinger S J & Feldman E C (eds) (2000) Textbook of Veterinary Internal Medicine. 5th edn. Philadelphia: W B Saunders & Co.
- Kaneko J J, Harvey J W & Brass M L (eds) (1997) Clinical Biochemistry of Domestic Animals. 5th edn. Boston: Academic Press.
- Duncan J R, Prasse K W & Mahaffey E A (1994) Veterinary Laboratory Medicine. Clinical Pathology. 3rd edn. Iowa: Iowa University Press.