ISSN 2398-2977      

Blood: biochemistry - urea

pequis

Synonym(s): Blood urea nitrogen, BUN


Overview

  • Produced in liver from ammonia derived from tissue/dietary protein and excreted by kidneys.
  • Important marker of kidney function and protein metabolism.
  • Quantity of urea in blood may be expressed as entire urea molecule (urea) or nitrogen portion (BUN - most common in USA).

Sampling

This article is available in full to registered subscribers

Sign up now to obtain ten tokens to view any ten Vetlexicon articles, images, sounds or videos, or Login

Tests

Methodologies

  • Urease (enzymatic method) most specific. No interference from free blood ammonia.
  • Typically measured as (total) blood urea nitrogen (BUN).
  • Blood strips can be used to get a rapid result. Do not give precise reading but will show if levels are significantly elevated.

Availability

  • Widely available.

Validity

Sensitivity


Increases in BUN do not occur until the majority of nephrons (about 75%) are non-functional. Complete loss of one kidney (provided that the other is fully functional) will not produce azotemia. Therefore, not very useful in evaluating early or minor changes in GFR

Specificity

  • Relatively non-specific. Alterations may occur with pre-renal, renal or post-renal conditions or diseases affecting other organs or systems.

Technique (intrinsic) limitations

  • Only significant in conjunction with other laboratory and clinical findings.
    Most useful to assess in conjunction with a urine specific gravity   Urine: specific gravity 

Result Data

This article is available in full to registered subscribers

Sign up now to obtain ten tokens to view any ten Vetlexicon articles, images, sounds or videos, or Login

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Ogilvie G K, Engelking L R & Anwer M S (1985) Effects of plasma sample storage on blood ammonia, bilirubin and urea nitrogen concentrations - cats and horses. Am J Vet Res 46 (12), 2619-2622.

Other sources of information

  • Kaneko J J, Harvey J W & Bruss M L (1997) Eds. Clinical Biochemistry of Domestic Animals. 5th edn. Academic Press, USA.

Organisation(s)

  • Veterinary commercial laboratories, State diagnostic laboratories or Veterinary College laboratories.

MEMBER BENEFIT

Can’t find what you’re looking for?

We have an ever growing content library on Vetlexicon so if you ever find we haven't covered something that you need please fill in the form below and let us know!

 
 
 
 

To show you are not a Bot please can you enter the number showing adjacent to this field

 Security code