Insight into your bile duct values.
Gamma-GT and alkaline phosphatase are enzymes that point more towards the bile ducts than towards the liver cells. Together they give insight into the drainage of bile.
Also known as: GGT, gamma-GT, alkaline phosphatase, ALP, bile ducts
Interpreted by BIG-registered doctors
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Background
What are gamma-GT and alkaline phosphatase?
Gamma-GT and alkaline phosphatase are enzymes found in abundance in the cells that line the bile ducts. If the drainage of bile stagnates, or if the bile ducts become irritated, these values rise in the blood. They therefore complement the liver tests ALT and AST: those point mainly to irritation of the liver cells themselves, while gamma-GT and alkaline phosphatase point more towards bile drainage.
Each enzyme has its own characteristics. Gamma-GT is sensitive to alcohol and to certain medicines, and is therefore often the first value to respond. Alkaline phosphatase comes not only from the bile ducts but also from bone. A rise therefore does not always fit the liver. By measuring the two together, the doctor can better judge whether the source lies in the bile ducts or elsewhere. If both are raised, that more often points towards the bile ducts.
In brief
Bile ducts
Both enzymes point towards bile drainage
Gamma-GT and alcohol
Gamma-GT is sensitive to alcohol and certain medicines
ALP is also in bone
A rise in ALP does not always fit the liver
More informative together
The combination helps interpret the source of a rise
Common reasons to test
When can insight into your Gamma-GT + ALP be valuable?
Below are some situations in which measuring Gamma-GT + ALP can provide insight.
Insight into your bile duct values
Gamma-GT and alkaline phosphatase assess the drainage of bile and thereby complement the liver tests.
With regular alcohol use
Gamma-GT is sensitive to alcohol. Those who want to know what their use does to this value have both enzymes measured.
With a raised liver value
If your ALT or AST is raised, these two enzymes help determine whether the bile ducts also play a role.
With long-term medication use
Various medicines can raise gamma-GT. Insight into these values is then relevant.
With questions about bone metabolism
Alkaline phosphatase also comes from bone. The value is therefore sometimes taken into account with questions about bone metabolism.
Tracking a value over time
For these enzymes the development over time is often more informative than a single measurement. Re-testing makes a change visible.
What your result means
How do we read your Gamma-GT + ALP level?
Gamma-GT and alkaline phosphatase are measured in units per litre (U/L). The laboratory states the reference values that apply there alongside your result. Important: alcohol, medication use, pregnancy, growth in young people and bone metabolism can influence these values.
A low value
A low gamma-GT generally has no medical significance. A low alkaline phosphatase is uncommon and is sometimes seen with certain nutritional or metabolic factors. Our doctor provides explanation and context with your result.
A normal value
Values within the laboratory's reference values give a reassuring picture of bile drainage at this moment. It remains a snapshot. The doctor always assesses your values together with your symptoms and your other liver values.
An elevated value
If gamma-GT and alkaline phosphatase are raised together, that more often points to stagnation or irritation of the bile ducts, for example due to gallstones or fatty liver. If only gamma-GT is raised, alcohol and certain medicines are common explanations. If only alkaline phosphatase is raised, the source may also lie in the bone, and during pregnancy or growth a rise is usual. A single measurement is not a diagnosis. Our doctor explains what your values mean and whether re-testing or follow-up via your GP is customary.
How we interpret your result
Our doctors interpret your gamma-GT and alkaline phosphatase against the laboratory's reference values and your personal context, such as lifestyle, alcohol use, medication use and any known conditions.
Related tests
Often combined with Gamma-GT + ALP.
A single marker gives one perspective. For a broader picture you can combine Gamma-GT + ALP with a theme package or related markers.
Frequently asked questions
Everything you want to know
Do I need to fast for this test?
No, you do not need to fast for gamma-GT and alkaline phosphatase. If you are also measuring glucose or cholesterol at the same time, fasting is customary.
What is the difference between gamma-GT and ALT or AST?
ALT and AST are found mainly in the liver cells and rise with irritation or damage to those cells. Gamma-GT and alkaline phosphatase come mainly from the cells around the bile ducts and point more towards the drainage of bile. They therefore complement each other.
Why is gamma-GT raised with alcohol use?
Gamma-GT responds sensitively to alcohol and to certain medicines. A rise does not automatically mean there is damage, but it does indicate that the liver is under load. The doctor takes this into account in the interpretation.
What does it mean if only my alkaline phosphatase is raised?
Alkaline phosphatase also comes from bone. If only this value is raised and your gamma-GT is not, the source may lie in bone metabolism rather than in the bile ducts. During pregnancy and in periods of growth a higher value is also usual.
Which medicines influence these values?
Various medicines can raise gamma-GT, for example some anti-epileptics, painkillers and antibiotics. Supplements and herbal preparations can also play a role. Please mention your medication with your result, so the doctor can take it into account.
Can a single elevated value mean a bile duct problem?
No. A single measurement is not a diagnosis. The doctor looks at the combination of both enzymes, at your other liver values and at your context, and advises whether re-testing or follow-up is useful.
How often should I have these values measured?
A single measurement is enough for initial insight. With a previously abnormal value or with a lifestyle change you want to follow, re-testing after a few months is customary.
What do I do with my result?
You receive a PDF report with your values and personal explanation. What you do with it, such as discussing it with your GP, remains entirely your choice.
Ready for insight into your bile duct values?
For €59 you receive your gamma-GT and alkaline phosphatase including personal explanation from a doctor, typically within a few working days. No referral required.
Order Gamma-GT + ALP for €64 →Want to test multiple markers at once?
Combine Gamma-GT + ALP with other markers via Bloodworks Select. Blood draw costs are waived from €225.
64,-
All-in, blood draw included