Fatty liver is very common, and for most people it stays a quiet finding. The question that matters is whether, over the years, the liver has started to scar. That scarring is called fibrosis. For a long time, the only way to look at it closely was a liver biopsy or a specialist scan. The Enhanced Liver Fibrosis (ELF) test offers a blood-based alternative, and it now has a defined place in UK guidance. This guide explains what the ELF test is, who it is usually meant for and how the score is read.
What liver fibrosis is
When the liver is irritated over a long period, by fat build-up, alcohol, viral infection or other causes, it repairs itself by laying down scar tissue. LML's description of the ELF test defines liver fibrosis as the scarring of liver tissue due to causes such as chronic liver disease, alcohol or viral infections. Fibrosis develops gradually and usually without symptoms. The NHS notes that most types of liver disease cause no symptoms in the early stages.
Why routine liver tests are not enough
Standard liver function tests (ALT, AST, GGT and others) show stress on liver cells and bile ducts at the moment of the test. They do not measure scarring. NICE guidance on metabolic dysfunction-associated steatotic liver disease (MASLD, previously called non-alcoholic fatty liver disease) is direct about this: do not use routine liver blood tests to assess advanced liver fibrosis in people with MASLD. A person can have normal ALT and still have fibrosis, or raised ALT with little scarring.
What the ELF test measures
The ELF test combines three markers involved in building and remodelling connective tissue. LML lists them as:
- Hyaluronic acid, a component of the tissue around liver cells.
- PIIINP, the amino-terminal propeptide of type III collagen, released when new collagen is formed.
- TIMP-1, the tissue inhibitor of metalloproteinase 1, which affects how scar tissue is broken down.
The three results are combined into a single score. A higher score suggests more active fibrosis.
How NICE uses the ELF test
NICE guideline NG49 sets out a clear pathway for people who have been told they have MASLD:
- Offer testing for advanced liver fibrosis, and consider using the ELF test for it.
- An ELF score of 10.51 or above, together with MASLD, is treated as advanced liver fibrosis, and NICE recommends referral to a liver specialist.
- People with a score below 10.51 are unlikely to have advanced fibrosis. NICE suggests retesting every 3 years for adults and every 2 years for children and young people, with no interim tests needed.
The guideline pairs this with advice about physical activity and diet, which is where most of the day-to-day work happens.
What research says about the ELF test
A Danish study published in the Journal of Hepatology compared the ELF test with two scores built from routine blood results (FIB-4 and the NAFLD fibrosis score) in more than 3,000 people from the general population and from groups at higher risk of alcohol-related or fatty liver disease (Kjaergaard et al., 2023). ELF produced far fewer false positives: 11%, against 35% and 45% for the other two scores, while keeping false negatives low. The authors concluded that ELF, alone or after FIB-4, reduces unnecessary referrals without overlooking true cases.
The British Society of Gastroenterology guidance on abnormal liver blood tests also discusses fibrosis assessment as part of the follow-up of abnormal results in primary care (Newsome et al., 2018).
