What it measures
- ALT
- AST
- ALP (alkaline phosphatase)
- GGT
- Bilirubin
- Albumin
What do liver function tests show?
Liver function tests (LFTs) are a group of markers:
- ALT and AST are enzymes released when liver cells are inflamed or damaged.
- ALP and GGT can rise when bile flow is blocked; GGT is also sensitive to alcohol.
- Bilirubin is a yellow pigment the liver processes. High levels can cause jaundice.
- Albumin is a protein the liver makes, reflecting how well it’s working overall.
Non-alcoholic fatty liver disease is now very common and often has no symptoms. Mildly raised enzymes are frequently the first sign, and lifestyle changes can make a big difference when it’s found early.
Who it’s for
- Regular alcohol use
- Being overweight or concerns about fatty liver
- Taking medicines that can affect the liver
- Yellowing of the skin or eyes, dark urine or tummy pain
How to prepare
- Drink plenty of water beforehand; it makes the sample quicker and easier to take.
- You don’t need to fast.
- Avoid alcohol for 24 hours before your test if you can.
Liver Function Blood Test: your questions
Can a blood test detect fatty liver?
Raised ALT or GGT can suggest fatty liver, but a normal result doesn’t rule it out. An abdominal ultrasound can show fat in the liver.
Information on this page is general and doesn’t replace advice from your GP, midwife or consultant. If you feel unwell or are worried about symptoms, contact your GP, call NHS 111 or, in an emergency, 999.