Bile acids test explained
- Updated
- 2026-09-10
- Every number with its source
What bile acids are and what the test shows
Bile acids are substances the liver makes from cholesterol and releases into bile, so that bile can help digest fats in the small intestine. After digestion most bile acids travel back to the liver in the bloodstream — this cycle is called the enterohepatic circulation — which is why the amount in the blood is usually very low. When liver cells are damaged, or when bile flow out of the liver or the bile ducts is disturbed, bile acids do not get back into bile and build up in the blood, so their level rises. That is why this test is used as an additional marker of liver function, especially when other liver tests (ALT, AST, bilirubin) do not give a clear answer, or when disorders of bile flow need to be assessed. Bile acids matter particularly during pregnancy: a rise together with itching may point to intrahepatic cholestasis of pregnancy (ICP), a condition that needs closer pregnancy care.
When bile acids are tested
- When the skin itches during pregnancy without a rash, especially the palms and soles, and the itching gets worse at night — when intrahepatic cholestasis of pregnancy (ICP) is suspected
- When other liver tests (ALT, AST, alkaline phosphatase, bilirubin) show deviations and bile flow needs to be assessed as well
- When a blocked bile duct or chronic liver disease is suspected
- To follow the course of a known liver or biliary tract disease
- When a doctor is assessing itching or jaundice of unclear cause
How to prepare
- Your doctor may ask you not to eat for a certain time before the test — follow those instructions, because the amount of bile acids can fluctuate depending on food eaten recently
- Tell your doctor about any known liver or gallbladder disease and about the medicines you take, as this can matter when the result is interpreted
The reference range
The exact reference interval depends on the laboratory's method, so you will find it on your own result sheet next to the result (how to read a result sheet). In general, the amount of bile acids in the blood of a healthy person is very low, because most of them are returned to the liver through the enterohepatic circulation.
A raised result
Raised bile acids show that bile flow out of the liver is disturbed, or that their circulation between the gut and the liver is. During pregnancy this may point to intrahepatic cholestasis of pregnancy (ICP) — according to the NHS there is then a small risk of premature birth (before 37 weeks), and with severe ICP also a small risk of stillbirth, which is why closer care is arranged. According to the NHS, most women with ICP recover completely and have a healthy birth. Outside pregnancy, a raised level is linked to diseases of the liver or the bile ducts.
What can raise bile acids
- Intrahepatic cholestasis of pregnancy (ICP) — a disturbance of bile circulation that appears in the last trimester of pregnancy
- A blocked or narrowed bile duct that disturbs bile flow out of the liver
- Chronic liver diseases that damage liver cells and bile production
- Cirrhosis of the liver
Symptoms that may go with it
- Severe itching of the skin without a rash, especially of the palms and soles
- Itching that gets worse at night
- Less commonly — the skin or the whites of the eyes may take on a yellowish tinge
What to discuss with a doctor
- Liver function tests (ALT, AST, alkaline phosphatase, bilirubin) alongside bile acids, so that the picture is clearer
- In pregnancy — discussing the care plan and more frequent pregnancy check-ups with your doctor
- During pregnancy, if the itching is severe (it keeps you from sleeping), if the palms or soles itch, or if the itching gets worse at night, the NHS says you need urgent medical help: do not wait for a routine appointment, and contact the doctor, midwife or maternity unit looking after your pregnancy the same day
- When to repeat the test, so that a change over time can be seen
Full site in Lithuanian: proactiva.app
Frequently asked questions
›What is the normal level of bile acids in blood?
The exact reference interval depends on the laboratory's method, so you will find it on your own result sheet next to the result. In general, the amount of bile acids in the blood of a healthy person is very low, because most of them are returned to the liver through the enterohepatic circulation.
›Why are bile acids tested during pregnancy?
During pregnancy, raised bile acids together with itching — especially of the palms and soles — may point to intrahepatic cholestasis of pregnancy (ICP). According to the NHS this is linked to a small risk of premature birth (before 37 weeks), so when ICP is identified, closer care of the pregnancy is arranged.
›Does itchy skin in pregnancy always mean there is a problem?
Not always — skin can itch in pregnancy for ordinary reasons, for example as the skin over the belly stretches. But if the itching is severe, without a rash, keeps you from sleeping or gets worse at night, especially on the palms and soles, the NHS says you need urgent medical help — contact the doctor, midwife or maternity unit looking after your pregnancy the same day, without waiting for a routine appointment. These can be signs of intrahepatic cholestasis of pregnancy (ICP), which needs prompt treatment; your doctor will order a bile acids test.
›How does the bile acids test differ from other liver tests?
ALT, AST and bilirubin show the general state of the liver cells, while bile acids specifically reflect bile production and the circulation of bile acids between the liver and the gut. That is why bile acids are especially useful when disorders of bile flow need to be assessed as well.
›Do I need to fast before a bile acids test?
Your doctor may ask you not to eat for a certain time before the test, because food eaten recently can temporarily affect the result. It is worth checking the exact preparation instructions with your own doctor or laboratory.
›What should I do if the bile acids result came back raised?
A result should always be discussed with a doctor: they will weigh it together with other liver tests, the symptoms and, where relevant, the course of the pregnancy, and decide on further monitoring or tests.
Sources
Related markers
This site is not an emergency service. If severe chest or head pain, breathlessness, confusion, difficulty speaking, heavy bleeding or another acute problem has come on suddenly — do not wait for tests, call 112.
This information is not a diagnosis and does not replace a consultation with a doctor. Reference ranges depend on the laboratory, your age and sex — always compare your result with the range printed on your own report.