Liver Function Test
Jan 31, 2026
Liver Function Test
A liver function test (LFT) measures key enzymes and proteins including ALT, AST, ALP, GGT, bilirubin, and albumin to assess how well your liver is working—crucial because liver damage often causes no symptoms until it's advanced. With fatty liver disease affecting 1 in 3 UK adults, regular liver testing is one of the most important health screens you can do.
At Blood Test London, liver function testing costs from £245 with results in 2-3 days.
What Does a Liver Function Test Measure?
Liver Enzymes
Marker | What It Shows | Normal Range |
|---|---|---|
ALT (Alanine Aminotransferase) | Liver cell damage | 7-56 U/L |
AST (Aspartate Aminotransferase) | Liver and muscle damage | 10-40 U/L |
ALP (Alkaline Phosphatase) | Bile duct issues, bone disease | 44-147 U/L |
GGT (Gamma-GT) | Bile duct issues, alcohol use | 9-48 U/L (men), 9-36 U/L (women) |
Liver Function Markers
Marker | What It Shows | Normal Range |
|---|---|---|
Bilirubin | Bile processing, jaundice risk | 3-17 μmol/L |
Albumin | Protein production | 35-50 g/L |
Total Protein | Overall protein status | 60-80 g/L |
Why Liver Health Matters
Your liver performs over 500 functions:
Filters toxins from blood
Metabolises alcohol, drugs, and hormones
Produces bile for fat digestion
Stores vitamins, minerals, and glucose
Makes proteins for blood clotting
Regulates cholesterol
The Silent Organ
The liver can function with significant damage before symptoms appear. By the time symptoms develop, disease may be advanced. This is why testing is essential.
Who Should Test Liver Function?
Test If You:
Drink alcohol regularly (even moderately)
Take regular medications (paracetamol, statins, etc.)
Are overweight or have diabetes
Have a family history of liver disease
Feel fatigued without explanation
Notice changes in digestion
Want a baseline for health monitoring
Conditions Detected
Fatty liver disease (NAFLD): Affects 1 in 3 adults
Alcohol-related liver disease: Various stages
Hepatitis: Viral or autoimmune
Drug-induced liver injury: From medications
Cirrhosis: Advanced scarring
Understanding Your Results
Elevated ALT
The most sensitive marker for liver cell damage.
Mild elevation (56-100): Often fatty liver, can be reversible
Moderate elevation (100-300): Needs investigation
High elevation (>300): Significant liver injury
Elevated GGT
Particularly sensitive to alcohol consumption.
Common in heavy drinkers
Also elevated with fatty liver
Useful for monitoring alcohol effects
Pattern Recognition
Pattern | Possible Cause |
|---|---|
ALT > AST | Fatty liver, chronic hepatitis |
AST > ALT | Alcohol-related damage |
Elevated ALP + GGT | Bile duct obstruction |
Low albumin | Chronic liver disease, malnutrition |
High bilirubin | Jaundice, liver or bile duct disease |
How to Optimise Liver Health
Diet
Limit alcohol: Maximum 14 units/week, with alcohol-free days
Reduce sugar: Fructose particularly harmful to liver
Eat whole foods: Fruits, vegetables, whole grains
Limit processed foods: Reduce unhealthy fats
Coffee: 2-3 cups daily may protect the liver
Lifestyle
Maintain healthy weight: Losing 5-10% weight improves fatty liver
Exercise regularly: Helps reduce liver fat
Avoid unnecessary supplements: Some harm the liver
Medications
Use paracetamol carefully: Stay within recommended limits
Avoid combining alcohol with medication
Discuss liver impact of any long-term medications with your doctor
Book Your Liver Function Test
Price: From £245
Results: 2-3 days
Doctor review: A doctor always reviews every result
Fasting required: No (but avoid alcohol 24 hours before)
FAQ
How often should I test my liver?
Annually for regular drinkers or those with risk factors; otherwise every 2-3 years.
Can fatty liver be reversed?
Yes—early-stage fatty liver often reverses with weight loss and lifestyle changes.
Does paracetamol damage the liver?
At recommended doses, it's safe. Exceeding 4g daily or combining with alcohol increases risk.
What if my results are slightly elevated?
Minor elevations are common and often improve with lifestyle changes. Your doctor will advise.
Should I stop drinking before a liver test?
Avoid alcohol 24-48 hours before for accurate results.
Blood Test London by The Wellness. Liver function testing from £245, results in 2-3 days.