GGT is a blood test that measures an enzyme concentrated in the liver and bile ducts, which rises with alcohol, fatty liver, impaired bile flow and oxidative stress. Practitioners use it to place a raised ALP in liver or bone, and as an early metabolic risk marker that responds quickly to lifestyle change. Enzyme-inducing medicines and kava can raise it without liver injury.
| Test type | Measured in a blood sample |
|---|---|
| Measurements required | GGT only |
| Sample and collection | Blood draw at a collection centre |
| Preparation | This test doesn't need fasting on its own. |
| Turnaround | 3 to 5 business days |
| Available through | Liver Function Tests, part of the Baseline Health Check. Also in: Full Body Health Check, Weight Management Test. |
| Pricing | Included in the $99 Baseline Health Check |
| Results | Returned in the Vively practitioner platform, beside your client's other markers |
What are the GGT reference and optimal ranges?
| Typical lab reference | Vively optimal | |
|---|---|---|
| Men | 5 to 50 U/L | 5 to 15.5 U/L |
| Women | 5 to 35 U/L | 5 to 10.5 U/L |
Labs differ, so read the client's result against the range on their report (RCPA guidance). The optimal range is deliberately tight and marks the lowest-risk end of the distribution; a value above it is a prompt to look at drivers, not a diagnosis.
Check a client's GGT result
Enter the value from your client's lab report to see where it sits against the typical lab range and the Vively optimal range.
A guide only, not a diagnosis. One result is a starting point: read it with symptoms, history and a repeat test. Labs differ, so check the result against the range on your client's report. Nothing you enter is stored or sent.
How do you arrange GGT testing through Vively?
- Get verified. Practitioners with a recognised qualification or membership (ATMS, NHAA, ANTA, Dietitians Australia, NSA, CMA or Ahpra registration) can request free practitioner access.
- Choose a panel. Log in to the practitioner platform and pick a panel that includes GGT, or build your own. It is included in the $99 Baseline Health Check.
- Client collects. Your client collects at a partner collection centre, with their request on their phone or printed.
- Review results. Results come back to you in the practitioner platform, beside your client's other markers, ready for the follow-up consult.
Which Vively panels include GGT?
Log in to the practitioner platform to view a panel in full, or build and save your own from 100+ tests and panels.
- Baseline Health Check74 markers across 11 lab groups$99
One fasting blood draw.
Full Blood CountUrea, Electrolytes & CreatinineLiver Function TestsCalcium, Phosphate & MagnesiumLipid StudiesDiabetes & Glycaemic StudiesIron StudiesThyroid Function Tests+3 moreLog in to view this panel - Weight Management Test27 markers · Heart & metabolicPrice on sign-upGGTTotal CholesterolLDL CholesterolHDL CholesterolNon-HDL CholesterolTriglyceridesFree testosteroneSHBG+19 moreLog in to view this panel
- Log in to view this panelFull Body Health Check87 markers · Health checksPrice on sign-up
Why does the optimal range sit there?
Our targets sit at the low end of the population distribution, well inside the lab range, because GGT predicts cardiovascular and metabolic outcomes within the reference range.
In the Vorarlberg cohort of 163,944 adults (Ruttmann, Circulation 2005), cardiovascular mortality rose step by step with GGT. Similar gradients have been reported for incident type 2 diabetes and metabolic syndrome.
GGT recycles glutathione, one proposed reason it tracks oxidative stress as well as liver injury.
Our targets are tighter than many published targets, so treat a value modestly above them as a lifestyle signal and watch the trend.
What should GGT be read with?
- HighHigh GGT with high ALP
Cholestatic pattern from a bile duct, gallstone or medicine cause; needs GP review.
- HighHigh ALP with normal GGT
The ALP is more likely coming from bone than liver.
- HighHigh GGT with high MCV, AST above ALT
Alcohol pattern, even when reported intake is modest.
- HighHigh GGT with high ALT, triglycerides and fasting insulin
Fatty liver (MASLD) with insulin resistance.
- HighHigh GGT with high ferritin and transferrin saturation
Alcohol or iron overload such as haemochromatosis; needs GP review.
What can affect a GGT result?
- Alcohol over the previous weeks; regular intake moves GGT more than a single night out.
- Enzyme-inducing medicines such as phenytoin, carbamazepine and phenobarbital, which can raise GGT without liver injury.
- Kava use, which is known to raise GGT.
- Body fat, fatty liver and smoking.
- GGT runs higher in men and rises with age.
When should you refer the client to their GP?
- GGT above three times the upper limit, or rising on repeat tests.
- Raised GGT with raised ALP or bilirubin, or with jaundice, dark urine, pale stools, itch or right upper abdominal pain.
- Raised GGT with high ferritin and transferrin saturation.
- GGT still raised after six to eight weeks of reduced alcohol.
How should a client prepare for a GGT test?
Copy or print this to send to your client.
Preparing for your GGT test
- This test doesn't need fasting on its own.
- If your practitioner has requested the Baseline Health Check, fast for 8 to 12 hours before a morning collection (water is fine).
- Take your pathology request to any of 4,000+ collection centres. Bring it printed or on your phone.
- Keep taking prescribed medicines as usual unless your doctor tells you otherwise.
- Results usually take 3 to 5 business days and come to your practitioner. Book your results appointment for after that.
How do practitioners use GGT with clients?
GGT is one of the most lifestyle-responsive liver markers. Cutting alcohol usually brings it down within four to eight weeks, and a whole-food diet lower in added sugar and processed fats, better sleep and weight loss where relevant help further, which makes it a good marker for showing a client progress on retest.
GGT FAQs
Can a naturopath, nutritionist or dietitian order GGT through Vively?
Yes. Add it to a client panel on the Vively practitioner platform. It is part of Liver Function Tests in the $99 Baseline Health Check, and is also in Full Body Health Check and Weight Management Test. No account yet? Request free access.
How soon after cutting alcohol should GGT be retested?
Allow six to eight weeks. GGT has a half-life of roughly two to three weeks, so levels fall over a month or more. A clear fall after cutting back supports alcohol as the driver; no change suggests fatty liver, a medicine or another cause worth raising with the client's GP.
Should I read GGT with ALP?
Yes. ALP comes from liver and bone, while GGT comes mainly from the liver and biliary tree. A high ALP with a raised GGT points to a liver or bile duct source. A high ALP with a normal GGT points to bone, such as growth, fracture healing or low vitamin D.
What raises GGT apart from alcohol?
Enzyme-inducing medicines such as phenytoin, carbamazepine and phenobarbital can raise GGT without liver injury. Kava, body fat, fatty liver and smoking also push it up, and it runs higher in men and rises with age. Pair it with ALT, triglycerides and fasting insulin to judge whether fatty liver with insulin resistance is the likelier driver.
When should a raised GGT go to the client's GP?
Involve the GP if GGT is above three times the upper limit, rising on repeat, or still raised after six to eight weeks of reduced alcohol. Do the same if it comes with raised ALP or bilirubin, high ferritin and transferrin saturation, or symptoms such as jaundice, dark urine, pale stools, itch or right upper abdominal pain.
References
- RCPA Manual. Gamma glutamyl transferase.
- Pathology Tests Explained. Gamma glutamyl transferase (GGT).
- Ruttmann E, Brant LJ, Concin H, et al. Gamma-glutamyltransferase as a risk factor for cardiovascular disease mortality: an epidemiological investigation in a cohort of 163,944 Austrian adults. Circulation. 2005.
- Healthdirect. Liver function tests. Source