Fatty Liver Blood Tests: LFTs, FIB-4 and What Next

Fatty liver disease means fat has built up in the liver. The condition long known as non-alcoholic fatty liver disease (NAFLD) is now also called metabolic dysfunction-associated steatotic liver disease (MASLD), and you may see either name on your results. The NHS says it is very common and more likely if you are overweight (particularly around the waist), have type 2 diabetes, polycystic ovary syndrome, high blood pressure or high cholesterol, or are over 50.

Most people only ever have the first stage, simple fatty liver, which does not usually cause problems. A smaller number develop inflammation (steatohepatitis), scarring (fibrosis) and eventually cirrhosis. Fatty liver rarely causes symptoms, so it is usually found after blood tests or a scan done for another reason. This guide explains which blood tests help, why normal liver tests do not rule it out, how the FIB-4 score is used to check for scarring, and what happens next.

Test it in Chiswick: our Liver Fibrosis Score (FIB-4) blood test costs £99, with your result explained in person by a practitioner. No GP referral needed. Book this test or call 020 4515 0000.

Quick answer

Fatty liver is often first suspected from liver function tests or an ultrasound scan, but routine liver blood tests can be normal even when there is scarring, so NICE says they should not be used to rule it out. Once fatty liver is found, the key question is fibrosis. The FIB-4 score, worked out from your age, ALT, AST and platelet count, is the usual first check. An indeterminate or high score leads to an ELF blood test or a FibroScan. HbA1c and cholesterol tests look for linked conditions such as diabetes.

Blood tests that can help

Liver function tests (ALT, AST and GGT)

A raised ALT, sometimes with a raised AST or GGT, is the most common way fatty liver comes to light. But NICE is clear: do not use routine liver blood tests to rule out NAFLD, and do not use them to assess for advanced fibrosis. A British Liver Trust summary of the NICE guideline notes that routine liver blood tests are commonly normal in NAFLD even when there is advanced fibrosis. Our Liver Health Check Plus (£49) covers ALT, AST, ALP, GGT, bilirubin, albumin and ferritin. For what the numbers mean, see ALT levels explained and liver function test results explained.

FIB-4 score

FIB-4 is a simple score calculated from your age, ALT, AST and platelet count. It estimates the chance of advanced scarring, and NHS pathways use it as the first step once fatty liver is found. In NHS pathways in South West London, for example, a FIB-4 below 1.3 (below 2.0 if you are over 65) means a low risk of advanced fibrosis, a high score means a high risk and referral to a liver specialist, and results in between are indeterminate and need a second test. Exact cut-offs vary between local pathways, and the score is less reliable in people under 35, where some services use the ELF test instead. Our Liver Fibrosis Score (FIB-4) test (£99) measures ALT, AST and platelets and reports the calculated score.

ELF test and FibroScan: the next step

If FIB-4 is indeterminate, the next step is usually an enhanced liver fibrosis (ELF) blood test or a FibroScan, a quick scan that measures how stiff the liver is. NICE guideline NG49 recommends considering the ELF test in people diagnosed with NAFLD to test for advanced fibrosis. Under NICE, an ELF score of 10.51 or above indicates advanced fibrosis and leads to specialist care, while adults with a score below 10.51 should be offered retesting every 3 years. Some local NHS pathways now use lower ELF thresholds to decide who needs a FibroScan or referral. We do not offer the ELF test or FibroScan, but your GP can arrange them, and our practitioner can include your FIB-4 result in a GP feedback report.

HbA1c and cholesterol

Fatty liver is closely linked with type 2 diabetes, high cholesterol and high blood pressure, and a British Liver Trust summary of the NICE guideline notes that NAFLD is itself a risk factor for type 2 diabetes, heart attack and stroke. One NHS pathway in South West London includes HbA1c and a lipid profile in its initial checks. Our Cholesterol and HbA1c Check (£59) covers both, and our guides to HbA1c levels and triglyceride levels explain the results.

Tests that rule out other causes

Before settling on fatty liver, doctors rule out other causes of abnormal liver tests. NHS pathways include ferritin in this liver screen, and viral hepatitis is another cause your doctor may want to exclude. Ferritin is included in the Liver Health Check Plus, and we also offer a Hepatitis B test (£49) and a Hepatitis C test (£49).

Alcohol

Alcohol can also cause fatty liver (alcohol-related liver disease), so your doctor will ask how much you drink, and alcohol can raise GGT on a liver test. The NHS low-risk guideline is to stay within 14 units a week if you drink most weeks, spread over 3 or more days.

Which test should I book?

• A focused start: Liver Health Check Plus, £49. ALT, AST, ALP, GGT, bilirubin, albumin and ferritin.
• A broader picture: Liver Fibrosis Score (FIB-4), £99. ALT, AST and platelet count with a calculated FIB-4 score, the usual next step once fatty liver is known.
• The fullest view: Metabolic Health Extended, £99. HbA1c, glucose, insulin, C-peptide, a full cholesterol profile with apolipoproteins and lipoprotein(a), hs-CRP and adiponectin. It does not include liver markers, so pair it with one of the liver tests above.

What blood tests cannot tell you

Blood tests cannot measure how much fat is in your liver. Fatty liver is usually confirmed with an ultrasound scan of your tummy, which your GP can arrange. Normal liver blood tests do not rule out fatty liver or scarring, and a raised ALT has many causes besides fat. FIB-4 is a risk estimate, not a diagnosis: a low score is reassuring, but a high or indeterminate score needs further tests rather than a conclusion.

When to see a GP urgently

Most people with fatty liver have no symptoms. Ask for an urgent GP appointment or call NHS 111 if:

• your skin or the whites of your eyes look yellow
• your tummy, legs, ankles or feet are swollen
• you are more short of breath than usual

Call 999 or go to A&E if you are vomiting blood, your poo is very dark or black, or you suddenly become confused or have slurred speech. These can be signs of serious liver disease. See your GP (non-urgently) if you think you could have fatty liver or are at higher risk.

Frequently asked questions

Can you have fatty liver with normal liver blood tests?

Yes. Routine liver blood tests are commonly normal in fatty liver, even when there is scarring. That is why NICE says not to use them to rule it out.

What is the difference between NAFLD and MASLD?

They describe the same condition. MASLD (metabolic dysfunction-associated steatotic liver disease) is the newer name, chosen to reflect the link with weight, blood sugar and cholesterol. NAFLD is still widely used.

What is a good FIB-4 score?

Many NHS pathways treat a score below 1.3 as low risk of advanced fibrosis, or below 2.0 if you are over 65. Higher scores need a second test or referral. Cut-offs vary between pathways, so discuss your score with your practitioner or GP.

Does a high ALT mean I have fatty liver?

Not necessarily. Fatty liver is a common cause, but alcohol, medicines, viral hepatitis and recent hard exercise can also raise ALT. Our guide to ALT levels explains the other causes.

How often should fatty liver tests be repeated?

NICE advises that adults with an ELF score below 10.51 are retested every 3 years, and some local pathways repeat FIB-4 every 2 to 3 years for people at low risk. Your GP or specialist will advise how often based on your results.

Fatty liver blood tests in Chiswick

Omnia Lifestyle is at 8 to 9 Bedford Corner, The Avenue, Chiswick, London W4 1LZ, a short walk from Turnham Green station (District line; Piccadilly line trains stop there early morning and late evening only) and served by buses 94, E3 and 272. Limited parking is available on request when you book. Every clinic test price includes your sample taken at the clinic, analysis at the Randox accredited laboratory, a practitioner review of your result with you, and a GP feedback report on request. You do not need a GP referral, and most results are back within a few working days.

Useful links: see all our liver function tests, book the Metabolic Health Extended panel, or compare every blood test and price. Our guides to liver function test results and blood tests for prediabetes cover related results. If you would like support alongside your GP care, see our metabolic health care at Omnia.

This article is general information, not medical advice. Discuss your results with your GP or practitioner.