Bile Acid Test

A bile acid test is used to measure the level of bile acids in the blood.

Bile acids are chemicals made by the liver that help digest fats. They are found in bile, a digestive fluid stored in the gallbladder. When food is eaten, bile acids are released into the duodenum (a part of the small intestine), which helps break down fats effectively. Abnormal bile acid levels are seen in conditions such as intrahepatic cholestasis of pregnancy (a liver condition that affects the flow of bile), primary sclerosing cholangitis (a condition that affects the bile ducts, which carry bile from the liver to the gallbladder), and primary biliary cholangitis (a chronic liver disease that damages the smaller bile ducts inside the liver).

Therefore, doctors recommend this test to assess liver function and monitor conditions affecting the liver and bile ducts.

Your doctor may recommend a bile acid test if you have symptoms or test results that suggest a problem with the liver, bile ducts, or bile flow, such as cholestasis. The following symptoms may also be considered:

• Dark-coloured urine
• Itching
• Pale-coloured stools
• Jaundice (yellowing of the skin and eyes)
• Pain in the upper abdomen (towards the right side)
• Inability to digest certain foods
• Nausea or loss of appetite
• Unexplained elevations in liver function tests

The test is also highly recommended for the following categories of people:

• Pregnant women – Pregnant women in the second half of pregnancy are susceptible to a certain kind of condition called intrahepatic cholestasis of pregnancy.
• Individuals with liver diseases – Individuals with alcohol related liver disease, such as alcoholic fatty liver, alcohol-associated hepatitis, and alcohol-associated cirrhosis, may experience problems with bile production or flow, resulting in cholestasis (reduction or blockage in the flow of bile)

The bile acid test can be used with other tests to help diagnose a few conditions:

• Intrahepatic cholestasis of pregnancy – This is a condition that occurs only during pregnancy. It affects bile production and can lead to serious complications for both mother and baby.
• Primary sclerosing cholangitis – A chronic disease causing inflammation and scarring of the bile ducts, leading to narrowing of the bile ducts and impaired bile flow.
• Primary biliary cholangitis – An autoimmune disease (a condition in which the immune system attacks its own healthy cells) that gradually destroys the small bile ducts inside the liver, causing reduced bile flow and liver damage.
• Jaundice – This condition causes your skin and eyes to turn yellow due to increased bilirubin levels in the body.
• Acute hepatitis – A sudden inflammation of the liver.
• Chronic hepatitis – This is a long-standing inflammation of the liver.
• Liver cancer – This is a type of cancer that starts in the liver or spreads to the liver from another part of the body.

What to Expect Before the Bile Acid Test

You must fast for 10 to 12 hours before the test. During the fasting period, drink plain water freely. Avoid all food, milk, tea, coffee, juices, and beverages other than water. Avoid smoking and alcohol for at least 24 hours, as both can falsely elevate triglyceride levels. Avoid strenuous exercise in the 24 hours before the test. Continue your regular medications unless your doctor advises otherwise. Morning appointments are strongly recommended.

What to Expect During the Blood Collection

A phlebotomist cleans the skin with an antiseptic, then places an elastic band around your upper arm to make the veins easier to access. A small needle is inserted into the vein; you may feel a brief pinch. Blood is collected into a labelled tube in under a minute.

What to Expect After the Bile Acid Test

A small cotton swab and bandage are placed over the site to stop any minor bleeding. You can eat and drink immediately after the test - have a light meal as soon as possible after the fast. If dizzy, sit and relax for a few minutes.

In the bile acid test, the primary parameter being measured is:

• The level of bile acids in the blood.

The normal range for the bile acid test is indicated in the table below.

Note: The normal range may vary slightly depending on the laboratory and individual medical condition.

The table below provides a general interpretation of the bile acid test results based on whether the levels are low or high.

Note: The results must always be interpreted along with clinical findings, symptoms, and other diagnostic tests.

Like any other medical test, this test also has certain risks and limitations.

Risks:

• The bile acid test is generally safe and involves minimal risk. You may experience slight pain when the needle is inserted or mild bruising afterwards, which usually resolves spontaneously.

Limitations:

• The bile acid test alone cannot diagnose a condition. Other tests, such as the bilirubin test and the alkaline phosphatase (ALP) blood test, help confirm the diagnosis.
• You may need to fast for 8–12 hours before the test, or as advised by your treating physician/doctor.

Depending on your symptoms and results, your doctor might recommend certain additional tests to better understand your condition:

• Alkaline phosphatase (ALP) test
• Liver function tests, including total bilirubin and liver enzymes (SGOT and SGPT)
• Anti-mitochondrial antibody test (to rule out primary biliary cholangitis)
• Bilirubin blood test
• Serum albumin test
• Ultrasound of the abdomen
• CT scan of the abdomen
• MRI of the abdomen
• Magnetic resonance cholangiopancreatography (MRCP)
• Endoscopic retrograde cholangiopancreatography (ERCP)