Equis ISSN 2398-2977

Blood: biochemistry - bile acids

Synonym(s): Bile salts

Contributor(s): Annalisa Barrelet, Kathleen P Freeman, Frank Taylor

Overview

  • Cholic and chenodeoxycholic acids (primary bile acids) synthesized in liver from cholesterol   →   conjugated with taurine and excreted in bile as their sodium salts (bile salts).
  • Discharged at time of eating to small intestine where they assist in fat digestion.
  • Only 2-5% of total bile acids are lost in feces each day - remainder resorbed, pass to the liver where extracted and re-excreted.
  • Small proportion reach general circulation - it is these that are measured.
  • Sensitive indicator of liver function and of integrity of liver, biliary and intestinal circulation.
  • The absence of a gall bladder in the horse means that bile acids are cycled continuously rather than released as a bolus at feeding. Therefore levels are not affected by feeding as in dogs.
  • Highest concentrations associated with biliary obstructive disease and portosystemic shunts.

Sampling

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Tests

Methodologies

  • Enzymatic: common.

Availability

  • Commercial laboratory, widely available.

Validity

Sensitivity

  • High sensitivity detection of decreased liver function.

Specificity

  • Low specifity in determining cause of decreased liver function.
  • Liver biopsy when [bile acid] elevated is necessary to determine specific cause   Liver: biopsy  .

Technique (intrinsic) limitations

  • Interpret results in conjunction with other laboratory results (liver enzymes).
  • Does not correlate with degree or type of liver disease. Prognosis depends on underlying cause.

Technician (extrinsic) limitations

  • Depends on methodology.

Result Data

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Further Reading

Publications

Other sources of information

  • Barton M H & Morris D D (1998)diseases of the Liver.In: Equine Internal Medicine.Eds: S M Reed & W M Bayly. Philadelphia: W B Saunders Co.
  • Kaneko J J, Harvey J W & Bruss M L (1997) EdsClinical Biochemistry of Domestic Animals.5th edn. Academic Press, Boston.

Organisation(s)

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


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