Overview

• Cholic and chenodeoxycholic acids (primary bile acids) synthesized in liver from cholesterol → conjugated with taurine (preferred) or glycine 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 via portal vein, where extracted and re-excreted (enterohepatic circulation).
• 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.

Sampling

Tests

Methodologies

• Enzymatic: more common (and accurate).
• Radio-immunoassay (RIA) (uncommon in veterinary laboratories).

Availability

• Widely available at commercial laboratories.

Validity

Sensitivity

• Increased by performing bile acid stimulation test.

Specificity

UK

• Liver biopsy when [bile acid] >30 umol/l (depending on laboratory's normal values) may give more indication of specific cause.

US

• Liver biopsy when [bile acid] 7.6 mg/l (depending on laboratory's normal values) may give more indication of specific cause Biopsy: hepatic.

Technique (intrinsic) limitations

• Measurements of total serum bile acids (TSBA) not indicated when jaundice is present because hyperbilirubinemia is present and increased affecting TSBA.
• TSBA may be warranted in icteric animal if hemolysis cannot be ruled out. If hemolytic disease is the cause of jaundice TSBA are expected to be within normal limits.
• RIA method less accurate.
• Interpret results in conjunction with other laboratory results (liver enzymes) and/or liver biopsy.

Technician (extrinsic) limitations

• Depends on methodology.

Result Data

Further Reading

Publications

Refereed papers

• Recent references from VetMedResource and PubMed.
• Allen L, Stobie D, Mauldin M & Baer K E (1999) Clinicopathologic fractures of dogs with hepatic or microvascular dysplasia with and without portosystemic shunts - 42 cases (1991-1996). JAVMA 214 (2), 218-220.
• Sevelius E (1995) Diagnosis and prognosis of chronic hepatitis and cirrhosis in dogs. JSAP 36 (12), 521-528.
• Tisdall P L, Tsoukalas G & Malik R (1995) Post-prandial serum bile acid concentrations and ammonia tolerance in Maltese dogs with and without hepatic vascular anomalies. Aust Vet J 72 (4), 121-126.
• Center S A, ManWarren T, Slater M R & Wilentz E (1991) Evaluation of 12-hour pre-prandial and 2-hour post-prandial serum bile acid concentrations for diagnosis of hepatobiliary disease in dogs. J Am Vet Clin Assoc 199 (2), 217-226.
• Sutherland R J (1989) Biochemical evaluation of the hepatobiliary system in dogs and cats. Vet Clin North Am Small Anim Pract 19 (5), 899-927.

Other sources of information

• Ettinger S J & Feldman E C (2000) Eds. Textbook of Veterinary Internal Medicine. 5th edn. W B Saunders & Co, USA.
• Kaneko J J, Harvey J W & Brass M L (1997) Eds. Clinical Biochemistry of Domestic Animals. 5th edn. Academic Press, USA.
• Duncan J R, Prasse K W & Mahaffey E A (1994) Veterinary Laboratory Medicine. Clinical Pathology. 3rd edn. Iowa: Iowa University Press.