Testing and Diagnosis for Primary Biliary Cholangitis

Learning you may have primary biliary cholangitis (PBC) is hard. You may not have any symptoms yet. It can be surprising to hear that you may have a liver problem.

Your doctor may do several tests to confirm a PBC diagnosis. It is normal to be stressed about your health during this time. This article explains common tests that doctors use. Talk to your doctors about what your test results mean.

How is primary biliary cholangitis diagnosed?

Most people with PBC do not have symptoms at the time of diagnosis. Doctors usually notice the first signs of PBC in routine bloodwork. They will consider PBC for:¹

• People with high liver enzyme levels and no bile duct blockage
• Women with unexplained itching, fatigue, or jaundice
• People with symptoms of linked conditions, like Sjogren’s syndrome

If doctors suspect PBC, they will perform several tests. Blood tests are the clearest indicators of PBC. Antimitochondrial antibodies (AMA) in the blood are the hallmark of PBC. Imaging tests will rule out other conditions. A liver biopsy can determine the stage of PBC.^1,2

What tests are used to diagnose primary biliary cholangitis?

Various tests are used to help diagnose PBC. They include the following:

Physical exam and health history

Many people with early stages of PBC do not have physical signs or symptoms. This can lead to a delayed diagnosis for some. It is possible, however, for doctors to find physical signs of PBC. Up to 40 percent of people with PBC have skin problems. Doctors may look for:^1,3

• Dark skin areas
• Yellowing of the eyes or skin (jaundice)
• Yellowish fatty deposits around the eyes or palms (xanthoma)
• Dry skin
• Scratches from itchiness
• Enlarged liver or spleen

Doctors may also look for symptoms of other autoimmune conditions. Certain conditions are common before or during PBC. Many people with PBC first show symptoms of Sjogren’s syndrome. Doctors will ask about your family history of autoimmune conditions.¹

Lab tests and blood work

Blood tests are the main way to diagnose PBC. These tests measure certain substances in the blood. Blood tests for PBC include:^1-3

• Alkaline phosphatase (ALP) – enzyme tested in regular liver function blood panels. Most people with PBC have very high levels of ALP.
• Antimitochondrial antibodies (AMA) – proteins made by your body that attack healthy mitochondria. About 95 percent of people with PBC have AMA. They rarely occur in people without PBC.
• Antinuclear antibodies (ANA) – proteins that attack the nucleus of healthy cells. About 70 percent of people with PBC have ANA.
• Cholesterol – Many people with PBC have very high cholesterol.
• Bilirubin – a chemical that gives bile its yellow color. Bilirubin levels are usually normal in the early stages of PBC. Higher levels indicate a more advanced stage.

High ALP level in regular bloodwork may be the first sign of PBC. Then, doctors will measure AMA levels to confirm a diagnosis. Monitoring bilirubin levels can help track PBC progression.¹

Imaging tests

Imaging tests help your doctor see inside your body. They may look at your liver and bile ducts. This can help confirm a diagnosis. It can also rule out other conditions. Common imaging tests include:^1-3

• Ultrasound – uses sound waves to create images. It can rule out a bile duct blockage.
• FibroScan – uses an ultrasound-like probe. It can detect liver scarring (cirrhosis)
• Magnetic resonance cholangiopancreatography (MRCP) – a special MRI of your organs and bile ducts. It can rule out a bile duct blockage.

Liver biopsy

In a liver biopsy, doctors take a sample of liver tissue. They will test it in a lab for signs of PBC. A biopsy is usually not needed to diagnose PBC. Blood tests are usually enough. But a liver biopsy can help doctors determine the stage of PBC.^1-3

If lab results and imaging are uncertain, a liver biopsy can help. For example, some people have normal levels of ALP but are positive for AMA. A liver biopsy can clarify the diagnosis.¹

What do my test results mean?

You should always talk to your doctor about the meaning of your results.

Many substances tested in bloodwork have a normal range. The normal range depends on age, sex, and other individual factors. Levels outside your normal range may indicate a health problem. Other blood test results do not give a number and can only be positive or negative.

A PBC diagnosis is confirmed if you have no other liver problems and at least 2 of the following:^1,3

• ALP levels of at least 1.5 times the upper limit of your normal range
• Positive for AMA
• Evidence from a biopsy analysis

If your results are uncertain, your doctor may suspect other conditions. Because PBC occurs in men less often than in women, a different diagnosis is more likely for men and people younger than 30 or older than 65.¹