Liver function (LFTs)
ALP blood test: what a high or low result means
What an ALP (alkaline phosphatase) result means, why ALP can be high, and what to ask your doctor.
Got your ALP result in front of you?
Paste your whole results sheet (or upload a photo, PDF or Word file) and Patiently AI explains it in plain English, sticking to the numbers and ranges on your report. Free, no account, and identifying details are removed on your device first.
Explain my results → Available on web, iOS & Android.What is ALP?
ALP, or alkaline phosphatase, is an enzyme found mainly in the liver, the bile ducts and the bones. It is part of the liver function tests (LFTs) and the bone profile. Because ALP comes from more than one place, a raised result is interpreted alongside other tests, such as GGT, to work out whether it is coming from the liver or the bones.
Why is this test done?
- As part of routine liver function tests or a bone profile
- To check for problems with the bile ducts
- To investigate bone pain or bone conditions
- To monitor liver or bone treatment
What does a high ALP mean?
A high ALP can come from the liver and bile ducts or from the bones. Some rises are completely normal.
Possible reasons include:
- Childhood and teenage growth spurts, when bones are growing
- Pregnancy, especially later pregnancy, when the placenta makes ALP
- A blockage or narrowing of the bile ducts, for example from gallstones
- Liver conditions
- Bone conditions such as Paget's disease or low vitamin D
- A healing fracture
- Less commonly, cancer affecting the liver or bones
What does a low ALP mean?
A low ALP is uncommon and often not significant.
Possible reasons include:
- Low zinc or magnesium, or malnutrition
- Rarely, an inherited condition called hypophosphatasia
Why we don't list a "normal range". Reference ranges differ between laboratories and can depend on your age, sex and whether you are pregnant. The range printed next to your result on your own report is the one that applies to you, so use that, and talk to your doctor about what your result means for you.
What can affect your ALP result?
- Age, as children and teenagers have much higher levels
- Pregnancy
- A recent fracture
- Eating a fatty meal before the test, in some people
Make sense of the whole report, not just one line
Results are easier to understand together. Patiently AI explains your report as a whole and writes personalised questions for your next appointment.
Try it with your own results → Paste, upload or photograph your results.Questions to ask your doctor
- Is my raised ALP coming from my liver or my bones?
- Should my GGT, calcium or vitamin D be checked?
- Do I need a scan?
- Should this be repeated?
Frequently asked questions
Why is my child's ALP so high?
Children and teenagers naturally have much higher ALP because their bones are growing. Labs use age-specific ranges, so check the range printed on the report.
How do doctors tell if high ALP is from the liver or bone?
They often look at GGT. If GGT is also raised, the ALP is probably from the liver. If GGT is normal, bone is a more likely source.
Is high ALP in pregnancy normal?
Yes. The placenta makes ALP, so levels often rise in later pregnancy.
Can Patiently AI explain my ALP result?
Yes. Paste your results, or upload a photo, PDF or Word file, and Patiently AI explains them in plain English, sticking to the numbers and ranges on your own report rather than adding its own, and suggests questions to ask your doctor. It is free, needs no account, and removes identifying details on your device first.