Bile acids algorithm

Use results to:

  • Assess liver function
  • Identify occult liver disease
  • Evaluate for vascular anomalies
  • Monitor patients on hepatotoxic medication

Clinical signs and diagnostic findings consistent with hepatobiliary disease

Clinical signs
Breed predilection
Poor growth in young animal
Poor recovery from anesthesia/sedation
Neurologic signs
History of hepatotoxic medication
Weight loss

Decreased and/or low normal MCV

Ammonium biurate crystals
Bilirubin (feline)

Chemistry panel
Decreased or low normal:

  • BUN
  • Albumin
  • Glucose
  • Cholesterol


  • ALT, AST, GGT, ALKP (persistent elevation or ≥ 3x upper end of reference interval)
  • Total bilirubin*

*If patient is icteric or if bilirubin is increased, rule out prehepatic causes and proceed without bile acids testing (see below).

2 or more of the above clinical indicators?

Consider extrahepatic diseases where appropriate; perform pre- and postprandial bile acids*


Preprandial: 0–14.9 μmol/L
Postprandial: 0–29.9 μmol/L

Preprandial: 0–6.9 μmol/L
Postprandial: 0–14.9 μmol/L

Does not rule out the presence of hepatobiliary disease

Mild elevation

Pre- or postprandial: 30.0–40.0 μmol/L

Pre- or postprandial: 15.0–30.0 μmol/L

Can be seen with both extrahepatic and hepatobiliary disease

Moderate to severe elevation

Pre- or postprandial: >40.0 μmol/L

Pre- or postprandial: >30.0 μmol/L

Consistent with hepatic dysfunction and/or cholestatic liver disease

Rule out extrahepatic causes

Consider supportive care and reevaluate as appropriate

Continued suspicion of primary hepatobiliary disease?

Investigate for underlying hepatobiliary disease

Increased bile acids and/or hepatic enzymes?

Evaluate for extrahepatic diseases

Possible causes

  • Pancreatitis
  • Gastrointestinal disease
  • Endocrine
    • Hyperadrenocorticism
    • Hyperthyroidism
    • Diabetes mellitus
  • Extrahepatic neoplasia
  • Hypoperfusion (congestive heart failure, shock)
  • Trauma
  • Drug induced (ALKP/GGT)
    • Steroids, phenobarbital
  • Muscular disease (ALT/AST)
  • Osteolytic disease/bone (ALKP)

Consider performing

  • Spec cPL Test/Spec fPL Test
  • Diagnostic imaging
  • Endocrine testing

Investigate underlying hepatobiliary disease

Possible causes

  • Inflammation (chronic hepatitis, cholangiohepatitis)
  • Infection (leptospirosis, bacterial cholangiohepatitis)
  • Toxicity (NSAID, phenobarbital, sago palm)
  • Vascular anomaly (portosystemic shunt, microvascular dysplasia)
  • Neoplasia (primary or metastatic)
  • Cholestatic liver disease
    • Lipidosis
    • Vacuolar hepatopathy
  • Cirrhosis
  • Biliary disease
    • Mucocele
    • Cholelith
    • Biliary neoplasia
    • Cholecystitis
  • Breed-related increase (Maltese)

Consider performing

  • Coagulation profile (PT/aPTT)
  • Ammonia
  • Diagnostic imaging
  • Cytology
  • Biopsy
    • Special testing as indicated (liver copper concentrations, liver culture)
  • Infectious disease testing