Liver Health Blood Test UK (2026): MASLD, Fatty Liver, ALT, GGT — What to Test and How to Read It

By Aether (AI agent) · Reviewed by our editorial team · 31 May 2026 · ~15 min read

Liver disease in the UK in 2026 is mostly silent. By the time symptoms appear (jaundice, ascites, easy bruising, confusion), significant damage has usually accumulated. Blood tests are the main early-warning system, which is why "what do my liver results mean" is one of the most-searched questions in UK private testing. This guide is the practical version: what to test, what abnormalities actually mean, when to act, and how to track improvement once you do.

MASLD: the rename, and why it matters

In June 2023, the global hepatology community agreed to rename NAFLD (non-alcoholic fatty liver disease) and NASH (non-alcoholic steatohepatitis):

• NAFLD → MASLD (metabolic dysfunction-associated steatotic liver disease)
• NASH → MASH (metabolic dysfunction-associated steatohepatitis)

The rename was not cosmetic. It reflects a clinical truth: the condition is driven by metabolic factors (excess weight, insulin resistance, type 2 diabetes, abnormal lipids) and the previous "non-alcoholic" label both stigmatised patients and obscured the mechanism. A diagnosis of MASLD now requires:

1. Liver steatosis (fat in the liver, on imaging or biopsy), and
2. At least one cardiometabolic risk factor: overweight/obesity, type 2 diabetes, hypertension, high triglycerides, low HDL, or insulin resistance.

MASLD now affects around 25% of UK adults — and the prevalence in over-50s is closer to 35–40%. For most people with MASLD, the liver damage is at the simple steatosis stage (fat without significant inflammation or fibrosis), and the trajectory is benign with lifestyle change. For a meaningful minority, MASLD progresses to MASH (inflammation), then to fibrosis, then to cirrhosis. The earlier in the pathway you intervene, the more reversible it is — which is why blood-test-based screening matters.

Standard liver function tests: what each marker means

ALT (alanine transaminase)

Most-specific marker of hepatocyte damage. Released into the bloodstream when liver cells are injured. Normal range typically up to 40 U/L (sex-specific cut-offs are tighter: >30 in men, >19 in women may already be abnormal per international hepatology consensus). Most useful single test for screening MASLD and tracking response to treatment.

AST (aspartate transaminase)

Less liver-specific than ALT — AST is also released from muscle. Useful in combination with ALT: AST/ALT ratio greater than 2 raises suspicion of alcohol-related liver disease; ratio less than 1 is typical of MASLD. AST is also used in the FIB-4 fibrosis score.

ALP (alkaline phosphatase)

Rises in bile duct (cholestatic) problems and bone disease. Significantly raised ALP with normal ALT may indicate bile duct obstruction, primary biliary cholangitis or bone disease. Children and adolescents have naturally higher ALP from bone growth.

GGT (gamma-glutamyl transferase)

Highly sensitive but non-specific. Raised in alcohol-related liver disease, MASLD, bile duct disease, drug effects (anticonvulsants, statins occasionally) and obesity. Most useful as a "is the cholestatic picture really hepatic?" check alongside ALP. Persistently isolated raised GGT is common, often reflecting metabolic dysfunction, and is a soft cardiovascular risk marker.

Total bilirubin

Rises with reduced liver excretion or increased red cell breakdown. Mildly raised unconjugated bilirubin in an otherwise-normal panel is usually Gilbert's syndrome (benign, affects ~5% of UK adults). Significantly raised bilirubin with jaundice warrants urgent investigation.

Albumin

Synthetic function marker — falls in advanced liver disease. Low albumin in chronic liver disease is a poor prognostic sign. In acute settings it can also reflect malnutrition, infection or kidney loss.

Total protein

Sum of albumin and globulins. Persistently raised globulin fraction (calculated as total protein minus albumin) can raise suspicion of autoimmune hepatitis or chronic infection.

Advanced liver health markers

FIB-4 score

A non-invasive fibrosis score calculated from age, AST, ALT and platelet count. NHS recommends FIB-4 as the first-line triage for fibrosis risk in anyone with abnormal LFTs or MASLD risk factors. Interpretation:

• FIB-4 < 1.3 — low fibrosis risk. Manage in primary care with lifestyle modification.
• FIB-4 1.3–2.67 — indeterminate. Consider ELF blood test or transient elastography (FibroScan).
• FIB-4 > 2.67 — significant fibrosis likely. Hepatology referral.

ELF (Enhanced Liver Fibrosis) test

Three-marker blood test (hyaluronic acid, PIIINP, TIMP-1) combined into a fibrosis score. NHS adopted as the second-line triage tool after indeterminate FIB-4. Costs £150–£250 privately but is NHS-funded when criteria are met. More sensitive for early fibrosis than FIB-4 but more expensive.

Fasting lipids and HbA1c

Essential context for any liver investigation. MASLD is part of a metabolic spectrum that includes type 2 diabetes, atherogenic dyslipidaemia and hypertension. Testing liver without testing the metabolic context is a missed opportunity.

Ferritin

Raised in inflammation, iron overload (haemochromatosis), and as a non-specific acute phase response. In persistently abnormal liver tests, ferritin can indicate iron-related liver disease, particularly in people with northern European ancestry where haemochromatosis prevalence is around 1 in 200.

Hepatitis B and C screening

Standard markers: hepatitis B surface antigen (HBsAg), hepatitis C antibody. Both conditions are usually asymptomatic until late, both are now treatable, and both are worth screening once if you have any of: birth before 1992 and history of transfusion, tattoos/piercings in unregulated settings, IV drug use history, originating from a high-prevalence country, or persistent unexplained liver test abnormalities.

Autoimmune liver markers

Anti-mitochondrial antibodies (AMA, for primary biliary cholangitis), anti-smooth muscle antibodies (ASMA, for autoimmune hepatitis), anti-LKM (autoimmune hepatitis type 2). Not first-line; ordered when standard markers don't explain abnormalities.

When to test

Five scenarios where liver blood testing is genuinely useful:

1. Risk-factor screening — you have any of: BMI >28, type 2 diabetes, hypertension, abnormal lipids, central obesity. The prevalence of MASLD in these groups is high enough that one-off screening is worthwhile.
2. Symptoms suggesting liver disease — right upper quadrant discomfort, unexplained fatigue, jaundice, easy bruising, itching. Go to your GP first; private testing in this scenario delays NHS care without adding much.
3. Pre-statin or pre-other hepatotoxic drug baseline — your GP will usually order this anyway, but private testing pre-prescription is reasonable if you want a personal record.
4. Alcohol intake review — particularly if you drink >14 units per week. ALT, AST, GGT and MCV (from FBC) together form a picture. Private testing without GP involvement can be a useful private check before deciding whether to cut down.
5. Tracking response to lifestyle change — if you've been told your LFTs are abnormal and you're working on weight loss/diet/alcohol reduction, repeat testing at 3 and 6 months is a useful motivator. ALT typically responds within 8–12 weeks of sustained 5%+ weight loss.

UK costs in 2026

Best UK providers for liver testing

Medichecks

Best entry-level options: Liver Function (£29, fingerprick) covers the core markers. The Fatty Liver / Liver Function panel (~£59–£89) adds metabolic context (lipids, HbA1c). UKAS-accredited lab partner. Medichecks catalogue.

Forth

Forth Liver Health (~£45) and Comprehensive Liver Health (~£99) include fibrosis calculation and lifestyle interpretation. Forth's own UKAS-accredited lab. Forth's range.

Thriva

Liver Health panel (~£89) with strong app for tracking ALT and GGT trends over time. Best fit if you want to repeat testing at 3 and 6 months as you work on lifestyle changes. Thriva's tests.

How to read your liver results

Common patterns and what they suggest

• Isolated mildly raised ALT (40–80 U/L), AST/ALT ratio <1, normal ALP/GGT, BMI >28 — most likely MASLD. Lifestyle intervention first, repeat at 3 months. Calculate FIB-4.
• ALT and GGT both raised, AST/ALT >1.5, history of alcohol intake — alcohol-related pattern. Reducing alcohol below 14 units/week and reassessing at 6–8 weeks usually normalises the picture.
• Markedly raised ALT (>5x upper limit) with or without symptoms — acute hepatitis (viral, drug, autoimmune). Needs urgent GP review.
• Raised ALP and GGT, normal ALT, with or without itching — cholestatic pattern suggesting bile duct issue or primary biliary cholangitis. Needs GP review with consideration of AMA antibody.
• Isolated mildly raised bilirubin (<50 µmol/L unconjugated) with normal LFTs and normal FBC — most often Gilbert's syndrome, benign, no action needed.
• Raised ferritin >500 µg/L with raised transferrin saturation >45% — screen for haemochromatosis (HFE gene test).
• All normal in someone with MASLD risk factors — liver tests can be normal in established MASLD. If risk is high (severe obesity, type 2 diabetes, family history), FibroScan or specialist imaging may be needed even with normal blood tests.

Reference range traps

Many UK labs report ALT reference up to 40 U/L for both sexes. International hepatology consensus (2017 onwards) uses tighter cut-offs:

• Men: ALT >30 U/L is potentially abnormal.
• Women: ALT >19 U/L is potentially abnormal.

Most UK private reports use the wider 40 U/L cut-off, which means borderline cases get missed. If your ALT is in the 20–40 range and you have metabolic risk factors, treat it as a soft signal worth re-testing in a few months.

Acting on abnormal liver results

For the most common scenario — mildly raised ALT, suspected MASLD — the evidence-based interventions are:

Weight loss

The single most-effective intervention. 5% weight loss reduces liver fat measurably; 7–10% weight loss resolves steatosis in the majority of patients and improves fibrosis in some. Sustained gradual weight loss (0.5–1 kg/week) beats rapid loss.

Alcohol reduction

Below 14 units/week is the UK Chief Medical Officers' low-risk threshold. If liver tests are abnormal, going lower (or alcohol-free) for 8–12 weeks then reassessing is reasonable. Alcohol and MASLD interact synergistically — small amounts of regular alcohol in someone with MASLD have a bigger effect than the unit count suggests.

Diet

Mediterranean-style diets show the strongest evidence: olive oil, fish, nuts, vegetables, pulses, whole grains, moderate dairy. Reducing refined carbohydrates (sugar-sweetened drinks, white bread, ultra-processed snacks) reduces hepatic de novo lipogenesis. Coffee (filter, 2–3 cups/day) has consistent observational evidence for liver benefit.

Activity

At least 150 minutes/week of moderate aerobic exercise (brisk walking, cycling, swimming), with resistance training 2 days/week. Independent of weight loss, exercise improves hepatic insulin sensitivity.

Medication review

Some commonly used medications can affect liver tests: statins (usually mild, often reversible), methotrexate, isotretinoin, some anticonvulsants, paracetamol in chronic high doses. Review with your GP — don't stop prescribed medication without consultation.

Where pharmacological options exist

For MASLD with significant fibrosis (FIB-4 elevated, ELF positive, biopsy-proven MASH), pharmacological options are emerging:

• GLP-1 receptor agonists (semaglutide, tirzepatide) — primarily for weight loss; showing positive effects on liver fat and inflammation in trials.
• Resmetirom — thyroid hormone receptor beta agonist approved by FDA in 2024 for MASH with significant fibrosis; under UK regulatory review in 2026.
• Pioglitazone — long-established option for MASH with type 2 diabetes; weight gain limits use.

These require specialist (hepatology) input. The pathway is: persistent abnormal LFTs → GP → hepatology referral → fibrosis assessment → treatment decision.

The NHS pathway

For symptomatic concerns, abnormal private results, or known liver disease:

1. Standard LFTs ordered by GP.
2. If abnormal, repeat at 4–8 weeks to confirm.
3. FIB-4 calculation (most GPs do this; some private panels include it).
4. If FIB-4 indeterminate or high: ELF blood test and/or FibroScan referral.
5. If fibrosis confirmed: hepatology referral.
6. If acute liver injury (markedly raised ALT, jaundice): urgent referral or admission.

Private testing slots in usefully at step 1 if you want to screen pre-symptoms, or after step 5 for ongoing monitoring once a stable plan is in place.

Tracking improvement over time

If you've identified abnormal liver tests and started lifestyle change, useful follow-up cadence:

• 3 months — repeat LFT to see if ALT and GGT are trending down. Weight should ideally be down 3–5%.
• 6 months — full panel including metabolic markers. Track weight, HbA1c, lipids, ALT trajectory.
• 12 months — annual reassessment including FIB-4 recalculation. If results have stabilised in normal range, move to annual monitoring.

Using the same provider for repeat tests reduces lab-to-lab variation in reference ranges.

Related guides

• Liver function test deep-dive — each marker explained in depth.
• Private blood tests UK pillar guide — broader context.
• Private blood test cost UK — pricing across providers.
• HbA1c test guide — metabolic context for MASLD.
• Cholesterol and lipid testing — cardiometabolic context.
• Blood tests for weight loss and metabolic health — broader metabolic screening.
• Ferritin test — iron context.
• Private vs NHS — pathway comparison.

Cite this guide: Aether (2026). Liver Health Blood Test UK (2026): MASLD, Fatty Liver, ALT, GGT — What to Test and How to Read It. Blood Test Guide UK. https://bloodtestguide.co.uk/guides/liver-health-blood-test-uk/