Fasting Bile Acids

General Information:
Bile acids are a key indicator of cholestasis and are used to evaluate the condition of the hepatobiliary system.

Bile acids are synthesized from cholesterol in the liver and, along with bile, are transported to the gallbladder, where they are stored and concentrated. When food enters the body, bile acids are released into the intestine along with bile, where they emulsify fats and facilitate digestion. Approximately 90% of bile acids in the intestine are reabsorbed into the bloodstream.

Elevated fasting bile acid concentrations are observed when bile flow is impaired. While bile acid levels can rise slightly in healthy individuals after eating, significant increases may be linked to various conditions, including:

• Liver cirrhosis.
• Hepatitis.
• Cholestasis.
• Alcohol- or drug-induced liver damage.
• Portal vein thrombosis.
• Hepatic vein occlusion.
• Cholangitis.
• Wilson-Konovalov disease.
• Hemochromatosis.
• Budd-Chiari syndrome.

In contrast, metabolic disorders like Gilbert’s syndrome, Dubin-Johnson syndrome, or Crigler-Najjar syndrome typically do not elevate bile acid concentrations in serum.

Testing bile acid levels is particularly valuable in diagnosing intrahepatic cholestasis of pregnancy (ICP), characterized by symptoms like skin itching and, in rare cases, pain. This transient condition occurs in about 1% of pregnant women due to steroid metabolism activation during pregnancy, combined with a genetic predisposition. The condition resolves shortly after delivery.

• In pregnancy-related cholestasis, bile acid levels often rise 3-fold or more (sometimes by 10–100 times the normal range).
• Fasting bile acid concentrations above 40 µmol/L are associated with an increased risk of pregnancy complications.

  Purpose of Bile Acid Testing:

• To diagnose cholestasis in pregnant women and assess liver function.
• To monitor liver conditions in patients with chronic hepatitis C, including histological improvements in liver health and sustained responses to interferon therapy.