High GGT on a Liver Test: What It Means

A high GGT means a liver and bile duct enzyme is above the lab's range. It is a common finding. The usual causes are alcohol, extra weight with a fatty liver, and some medicines. On its own, high GGT cannot tell what is wrong. A doctor reads it with your other liver tests, your drinking and your medicines.

Dr. Pedro Yelamo Vera is a GP licensed in Spain (Colegiado No. 484814280).

For a medical emergency, call 112 or go to the nearest local emergency department. Do not wait for a video consultation or an online reply.

What is GGT on a blood test?

GGT is an enzyme. Most of it comes from the liver and the bile ducts. When these are under strain, more GGT leaks into the blood.

MedlinePlus lists other names: gamma-GT, GGTP and gamma-glutamyl transpeptidase. On a Spanish report you may see GGT, gamma GT or gamma glutamil transferasa. It often sits next to GOT (AST), GPT (ALT), fosfatasa alcalina (ALP) and bilirrubina.

What is a normal GGT level?

MedlinePlus gives a normal adult range of 5 to 40 units per litre (U/L). Labs differ a little, so always check the range printed next to your result. Spanish labs often write U/L or UI/L. A few use µkat/L, where MedlinePlus gives 0.08 to 0.67.

A star, an arrow or an "H" next to the number means it is above that lab's range.

Is GGT tested in the UK, the US and Spain?

It depends on where your blood was taken:

• UK: the British Society of Gastroenterology lists GGT in the first set of liver tests, with bilirubin, albumin, ALT and ALP.
• US: the routine comprehensive metabolic panel (CMP) does not include GGT, per MedlinePlus. Doctors order it on its own, often to explain a high ALP.
• Spain: GGT is often part of a routine perfil hepático, so many people see it for the first time on a check-up.

So if you moved from the US, you may never have had a GGT result before. A new high value may not be new at all.

What causes a high GGT?

The British Society of Gastroenterology says GGT is most often raised by obesity, too much alcohol, or medicines. MedlinePlus lists other causes too:

• Alcohol. Drinking raises GGT. Most people with alcohol use disorder have a high level.
• Fatty liver linked to extra weight, diabetes or high blood fats.
• Medicines. MedlinePlus names paracetamol, carbamazepine, phenytoin and phenobarbital. MSD Manuals adds some other anti-seizure medicines and warfarin, plus some herbs.
• Blocked bile flow, for example from gallstones in a bile duct.
• Hepatitis (an inflamed liver) or cirrhosis (a scarred liver).
• Other conditions: heart failure, pancreas disease, lung disease and, rarely, a liver tumour.

Smoking and recent meals can also affect the result, says MedlinePlus. GGT goes down after eating.

What does high GGT with high ALP mean?

ALP comes from the liver and also from bone. GGT helps tell them apart:

• High ALP and high GGT: points to the liver or bile ducts, says MedlinePlus.
• High ALP with normal GGT: a bone cause is more likely. The British guideline notes this can be low vitamin D.
• High GGT with normal ALP: often alcohol, weight or medicines. MSD Manuals says this pattern can be seen in alcohol-related hepatitis.

MSD Manuals also notes that GGT does not rise from bone, in childhood or in pregnancy. That makes it useful when ALP is high in a pregnant woman or a growing child.

Is a high GGT serious?

Often it is not dangerous in itself. But it is worth taking seriously. The British guideline makes three points:

• GGT is not specific: many things raise it.
• Even so, a raised GGT is one of the best signs of future liver risk. It is also linked to a higher risk of death from all causes.
• The size of the rise is not a guide to how serious it is.

So a mild rise should not be ignored, and a large one is not always bad news. What matters is the cause.

How can I lower my GGT?

Treat the cause. For most people that means:

• Cutting down on alcohol, or stopping. Be honest with your doctor about how much you drink.
• Losing some weight if you carry extra, with more activity.
• Reviewing your medicines and supplements with a doctor. Do not stop a prescribed medicine on your own.

The British guideline says a high GGT can help people change their drinking. Your doctor may repeat the test after a period of change to see if it has fallen.

What happens next?

• Mild rise and an obvious cause: change what you can and repeat the test.
• No clear cause, or other liver tests are also high: a liver screen. This means more blood tests and often an ultrasound scan.
• GGT over 100 U/L in someone who drinks a lot: the British guideline advises a check for liver scarring.
• Still abnormal with no cause found: a referral to a liver specialist.

See a doctor today, without waiting, if your skin or the whites of your eyes turn yellow. This can come with itchy skin, dark pee and pale poo. Call 112 if you vomit blood or have black, tarry stools, or if you become confused or very drowsy.

Talking it through with a doctor by video

Dr. Yelamo is a GP licensed in Spain. He sees adults, children and pregnant patients by video, every day from 07:30 to 20:30 (Spain time). In the visit he will:

• Read your full report, not just the GGT line.
• Ask about alcohol, medicines, supplements and your weight.
• Compare it with past results, including ones from the UK or the US.
• Explain whether you need a repeat test, more tests or a specialist.

He does not promise any test or prescription before the visit. Where clinically appropriate, following a genuine evaluation. Treatment and prescriptions are issued solely at the doctor's discretion based on evidence-based clinical guidelines.

A prescription is never guaranteed: it is issued only where clinically appropriate after a genuine evaluation, as a private electronic prescription under Spanish law. This service is for urgent, non-emergency care. In an emergency, call 112.

See how the Urgent Care video visit works. It lasts 15 minutes and costs €50.

This guide is general information. It does not replace a consultation with your doctor.

Frequently asked questions

Sources

• MedlinePlus: Gamma-glutamyl transferase (GGT) blood test
• MedlinePlus: GGT test
• Newsome et al., Gut: British guidelines on abnormal liver blood tests
• MSD Manuals: Laboratory tests of the liver and gallbladder
• MedlinePlus: Comprehensive metabolic panel
• NHS: Jaundice

Related guides

• High ALT liver enzymes explained
• High bilirubin on a blood test
• Fatty liver and weight loss
• Blood testing in Spain
• Blood test results review online
• Fatty liver care