Type of test Blood

Normal findings

 Cholic acid (CA): 0-1.9 μmol/L

 Chenodeoxycholic acid (CDC): 0-3.4 μmol/L

Deoxycholic acid (DCA): 0-2.5 μmol/L

Ursodeoxycholic acid (UDC): 0-1 μmol/L Total: 0-10 μmol/L

Test explanation and related physiology

Primary bile acids are formed in the liver from cholesterol, conjugated primarily to glycine and taurine, stored and concentrated in the gallbladder, and secreted into the intestine after the ingestion of a meal. In the intestine, the bile acids emulsify ingested fats and promote fatty digestion. During absorption of fat, nearly all of the bile acids are reabsorbed. The bile acids are then carried through the portal system to the liver. The hepatic clearance of bile acids from portal blood maintains serum concentrations at low levels in normal people.

Elevated fasting serum levels are due to impaired hepatic clearance and are a sensitive indicator of liver diseases, including cirrhosis, hepatitis, cholestasis, portal vein thrombosis, Budd Chiari syndrome, cholangitis, Wilson disease, and hemochromatosis. This test is also helpful in monitoring patients receiving bile acid therapy, such as cholic acid, deoxycholic acid, or ursodeoxycholic acid.

Interfering factors

 • Meals: Gallbladder contraction will result in an extra load of bile acids being excreted into the intestine and reabsorbed. Thus higher concentrations are expected.

Procedure and patient care

• See inside front cover for Routine Blood Testing.

• Fasting: Yes

• Blood tube commonly used: Red

Abnormal findings

Increased bile acids

- Primary hepatocellular diseases

- Cholestasis

- Metabolic diseases of conjugated bile acids

- Portal vein obstruction

- Cirrhosis

Decreased Bile Acids

- Malabsorption

- Metabolic abnormalities in bile acid synthesis