In many cases, a suspected diagnosis of primary biliary cirrhosis (PBC) is made after having a blood test for another, unrelated condition.
Damage to the bile ducts and liver leads to an increase in enzymes produced by your liver. The high level of enzymes can be detected by certain routine blood tests.
A diagnosis of PBC can usually be confirmed by checking your blood for anti-mitochondrial antibodies (AMAs). In PBC, AMAs are produced by the immune system (the body's natural defence against infection and illness). They are present in around 95% of people with PBC.
You may also have a high level of bilirubin in your blood. Bilirubin is a yellow substance produced when red blood cells are broken down. The liver usually "takes up" bilirubin from the blood and it is passed out of your body in urine.
If there is something wrong with your liver or bile ducts, bilirubin cannot be moved into the bowel and leaks back out into the blood. This shows up on a blood test.
You may also have an ultrasound scan to help rule out other problems with your bile ducts, such as a blockage caused by bile duct stones.
This is a painless scan, similar to the scan carried out during pregnancy, that involves using a probe that emits high-frequency sound waves to create an image of the inside of your tummy.
An ultrasound scan can also be used to assess the stiffness of your liver and identify any scarring (cirrhosis).
You may sometimes be referred for a liver biopsy. This involves removing a small sample of liver tissue so it can be studied under a microscope.
Most liver biopsies can be carried out under local anaesthetic to numb your skin. The sample is obtained using a long needle inserted through your tummy.
A liver biopsy is not always necessary to diagnose PBC, because it is usually confirmed by the presence of AMAs, but it can be used to assess the extent of damage to your liver and, increasingly, suggest the right treatment for you.