GGT: what it is, why we test it and what to do if it is high

GGT, or gamma GT, is an enzyme of the liver and the bile ducts. It is the liver test that reacts most to alcohol, but it also often rises with a few extra kilos or with some medicines. If it is high, one of these is usually the cause.

Why we test it

GGT is found in the cells of the liver and the bile ducts, the channels that carry bile. It rises when the liver is under strain, above all from alcohol, fat or medicines.

With alcohol it moves before the transaminases do. That is why it helps show where a liver problem comes from.

It matters beyond the liver too: in studies, a high GGT is linked to more health risks over the years. It often comes down once the cause goes.

What it tells you, and what it does not

If it is high, something is straining your liver or bile ducts. Extra weight, alcohol or some medicines are usually behind it.

It is very sensitive, but on its own it does not say why it rose.

If it is low, it is usually a good sign.

That is why it is read together with other tests:

Normal GGT levels

The lab decides what is normal. It is usually 5 to 36 U/L for women and 8 to 61 for men. Your own report may print different limits.

It is usually higher in men. Weight matters too: with a few extra kilos it tends to rise, even without alcohol.

In the Rosa report you also see your optimal range, read together with your liver enzymes and bilirubin.

What your result means

Find the row for your result, in U/L. Which values are dangerous? Any value above your report’s limit should be shown to your doctor, and above 100 soon.

High or low GGT

What causes high GGT

The first three are the most common.

Symptoms of high GGT

Usually none: a high GGT on its own is often found by chance, on a blood test.

If there are symptoms, they come from the cause. If bile is not flowing well, you may notice:

With yellow eyes or skin, dark urine or pale stools, see a doctor today. If you also have a fever or bad pain in your belly, call 112 or go to the emergency department. For itching alone, talking to your doctor is enough.

High GGT without drinking

This happens a lot. In people who drink little, the most common cause is fat in the liver, usually with a few extra kilos. Some medicines raise it too.

Sometimes alcohol is involved all the same. GGT is more sensitive than people expect: with age and a few extra kilos, even a few drinks a week can push it up a little.

If you do not drink and your weight is normal, your doctor looks for other causes, for example in the bile ducts.

How to lower your GGT

It comes down when the cause goes away. Where to start:

What can skew the result

A few things change the number for a while. It helps to know them before you read it.

When to worry

Talk to your doctor if:

With Rosa, a GGT above 100 U/L is always flagged to a doctor.

Frequently asked questions

High GGT: when should I worry? It is usually not an emergency, but it should always be looked into with your doctor, even if only slightly high. Talk to your doctor soon if it is above 100, or if your alkaline phosphatase or bilirubin is high too. With yellow eyes or skin, dark urine or pale stools, see a doctor today.

Can a high GGT mean cancer? Rarely: extra weight, alcohol or medicines are usually behind it. Less often the cause is a blocked bile duct or a liver disease, sometimes a tumour. In those cases alkaline phosphatase or bilirubin often rise too: that is why it needs looking into with your doctor.

High GGT with other liver tests: what does it mean? With high transaminases, a fatty liver or alcohol is usually behind it. With high alkaline phosphatase, bile may not be flowing well: talk to your doctor soon. With normal transaminases, alcohol, weight or medicines are often the cause.

Are normal values different for women and men? Yes: it is usually higher in men, and many reports print a different limit for women and men. The one printed on your report is what counts.

What should I do if my GGT is high? Show your report to your doctor and tell them how much you drink and what medicines you take. Meanwhile, cut down on alcohol and, if needed, work on your weight: these are the most common causes.

How often should it be checked? For people who feel well there is no fixed rule: Rosa measures it once a year. If it is high, your doctor decides when to check it again.

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