There is no single blood test to diagnose PSC or measure its progression.
However, liver blood tests are an important and regular part of the management of PSC. The tests give an indication of how well your liver is functioning and the kind of damage happening in your liver and bile ducts 52,58.
They are conducted every 6-12 months, or more frequently depending on your condition.
Your blood tests are usually carried out at your hospital or GP’s surgery. PSC Support recommends that you ask for a copy of each blood test result, so you have a complete picture of your blood history over time. Unfortunately, not all hospitals and GPs can access each other’s results, so it helps if you can track the complete picture. This way you can see straight away if your results are stable, and they are very useful to take on hospital visits to show your consultant.
PSC Support liver blood test tracker
PSC Support has a downloadable liver blood test Tracker that produces a graph, thanks to member, Kevin McCabe.
What’s important about liver blood tests in PSC?
Your doctor is interested in how consistent your blood tests are over time and will look for trends. If they are stable, then your doctor will not be concerned.
Your doctor will look at the pattern of injury to identify the prominent process involved as the test results do not necessarily show the severity of injury. For example, the hepatocytes (liver cells) that are injured cause liver enzymes to leak out into the blood, and a high ALT result may reflect a young healthy person with a liver injury (with liver cells causing a lot of ALT to leak out). On the other hand, a person with cirrhosis may have a low ALT, because there are fewer liver cells left leaking out ALT.
Some people have blood tests that are completely out of the normal range for years, yet they feel well and don’t have any problems. Other patients have blood tests that are not as bad, yet suddenly develop symptoms. Therefore, it is important to understand past liver blood test trends to help predict what will happen in the future.
Liver blood tests explained
Liver blood tests are sometimes referred to liver function tests (LFTs) but this is somewhat outdated because the blood gives more information than just liver function.
- Alkaline Phosphatase (ALP) - high levels can indicate damage or obstruction in the bile ducts. It can also be raised in non-liver issues such as: the presence of bone disease, fractures, heart problems, pregnancy. It is also common for young people to have raised ALP levels.
- Gamma-Glutamyl Transferase (GGT) - high levels of GGT may indicate liver damage. This is used to understand whether the elevated ALP relates to liver or non-liver issues. Because ALP is not a reliable marker for PSC in children, GGT is considered to be a more specific marker of bile duct injury in children, and children tend to have much higher levels of GGT, AST and ALT than in adults 130.
- Alanine Aminotransferase (ALT) and Aspartate Aminotransferase (AST) - measure damage in your liver cells (hepatocytes).
- Bilirubin - informs about how your liver is functioning. It is cleared by the liver and high levels can indicate a blockage of the bile ducts or liver damage. It means that your liver is no longer breaking down waste properly and can cause jaundice (where your skin and eyes appear yellow).
- Albumin - informs about liver function. It is a protein that is only produced in the liver. Low levels can indicate a liver which is not functioning properly.
- INR (international normalised ratio) - informs about how the liver is functioning by showing how quickly the blood clots. A higher INR can also reflect vitamin K deficiency.
Enhanced Liver Fibrosis (ELF) Test
The ELF test is a blood test that measures three parameters involved in the process of developing fibrosis. A score is then calculated to give an estimate of the severity of fibrosis in your liver and can be used to make an estimate about what might happen to you 42,43.
There is more detailed information about liver blood tests in the 2017 British Society of Gastroenterology Guidelines on the Management of Abnormal Liver Blood Tests (co-authored by PSC Support):