Liver and bone markers
High ALP but Normal Liver Function: Bone or Liver?
Reviewed by a qualified clinician · analysed at UKAS-accredited UK labs (ISO 15189)
Last reviewed September 20265 min read
Every Helvy guide is written by our health editors, then checked by a qualified clinician before it goes live and re-checked as the science moves. We name clinical roles, not individuals, until each reviewer has agreed to be credited publicly. This is wellness guidance to help you understand your own data, not a diagnosis.
QUICK ANSWER
Alkaline phosphatase comes from bone as well as liver, so a raised ALP beside a normal ALT often points at bone. British Society of Gastroenterology guidance says a GGT test separates the two, because GGT is present in the liver but not in bone. Vitamin D deficiency is the most common cause.
Not sure which markers you need? Build your test →One line on your liver panel is flagged and the rest are not. The ALP is up. The ALT, the one everybody calls the liver number, is sitting mid-range. You have spent an evening reading about liver disease and none of it quite fits.
There is a good reason for that. ALP is not only a liver enzyme, and the pattern you are holding usually points somewhere else.
1. ALP comes from two places
Your liver, and your bones.
Alkaline phosphatase, shortened to ALP, is an enzyme. An enzyme is simply a protein that speeds up a chemical job. This one is made in the bile ducts of the liver and also by the cells that build bone. Both feed the same number on your report.
That is the whole difficulty. The lab prints one ALP and does not say which source it came from.
It is grouped with the liver tests by habit, which is why a raised ALP reads as a liver alarm. Our ALP blood test guide covers the marker itself.
2. Why does a normal ALT change the reading?
Because ALT only comes from one place.
ALT sits inside liver cells and leaks out when those cells are under strain. Bone does not make it. So a normal ALT says the liver cells themselves look untroubled.
A raised ALP with a normal ALT is called an isolated raised ALP. That phrase is worth knowing, because it is what a clinician will write and what the guidelines are organised around.
If both numbers were up, the reading would be different. Our guide to high ALT levels covers that pattern, and the liver function test guide explains how the panel works as a set.
3. Which test settles bone or liver?
GGT. The British Society of Gastroenterology guidelines explain why it works.
“GGT is abundant in the liver and also present in the kidney, intestine, prostate and pancreas but not in bone; therefore it can be useful in confirming that an elevated ALP is of liver and not bony origin.”
So the logic runs like this. A raised ALP with a raised GGT points towards the liver. A raised ALP with a normal GGT points away from it, and bone moves up the list.
One honest limit before you go looking. GGT is not part of any Helvy panel. It is a GP or hospital request. The same guidelines describe repeating the liver blood tests with that marker added as the usual next step.
Our GGT blood test guide explains what that marker measures, so you know what you are asking for.
4. What usually lifts ALP on its own?
The BSG guidelines name the likely candidates for an isolated raised ALP, and the first one is ordinary.
- Vitamin D deficiency. Described as the most likely cause, and common in the UK.
- Rapid growth in childhood. A normal rise while bone is being laid down quickly.
- Paget’s disease of bone. A condition that speeds up bone turnover.
- Bone secondaries. Uncommon, and a reason this is a GP conversation rather than a search engine one.
Vitamin D is the one worth knowing about, because a shortage makes bone cells work harder and ALP rises with them. Our guide to vitamin D deficiency covers how common it is here and how it is measured.
Calcium, phosphate and vitamin D are usually read together when bone is the question. Our guide to bone health blood results sets out what each one adds.
5. What should you do next?
Take the result to your GP and ask two questions.
- Can we add a GGT? That is the test that separates liver from bone.
- What is my vitamin D? The most likely explanation, and easy to check.
How far above the range the number sits matters as well, and so does your age. ALP is naturally higher in teenagers and shifts again later in life. Our guide to ALP levels by age shows that spread.
A blood test measures the marker. Only a qualified clinician can put it beside your history and say what it means for you.
6. Which blood test reports ALP?
Helvy’s Thyroid & Vital Organs panel (£159) reports ALP and ALT together, with albumin, total protein, kidney markers, thyroid markers and a full cholesterol profile. Seeing ALP beside ALT is what turns one flagged line into a pattern.
Two honest limits. The panel does not include GGT, and it does not include calcium or phosphate. If bone is the question, your GP holds those.
Not sure which fits? The build-my-test tool walks you through it, and the metabolic health hub collects our liver and organ guides.
READY TO TEST?
See ALP and ALT on the same report
Helvy’s home blood tests report the liver markers as a set, so no single enzyme has to carry the story alone. Samples are processed by UKAS-accredited UK labs.
Frequently asked questions
Can ALP be high when the rest of the liver tests are normal?
Yes. It is common enough to have its own name, an isolated raised ALP. Because bone also makes ALP, the liver is often not the source.
Does a high ALP with a normal ALT mean liver disease?
Not on its own. ALT leaks from liver cells and is not made in bone, so a normal ALT points away from the liver cells. A GGT is the test that separates the two sources.
What is the most common cause of a raised ALP?
The British Society of Gastroenterology guidelines say vitamin D deficiency is the most likely cause of an isolated raised ALP, or the normal rise seen in childhood during rapid growth.
Why does GGT tell you whether it is bone or liver?
Because GGT is abundant in the liver and is not present in bone. A raised GGT alongside a raised ALP supports a liver source. A normal GGT makes bone more likely.
Does Helvy test GGT?
No. GGT is not part of any of our panels. Our Thyroid & Vital Organs panel reports ALP and ALT. Ask your GP for that one.
Should a slightly raised ALP be repeated?
Repeating the liver blood tests with a GGT added is the usual next step in the guidelines. Ask your GP when to repeat and what to add.
Related guides
High ALP Levels UK
What a raised alkaline phosphatase means more broadly.
ALP Levels by Age UK
Why one printed range does not fit every age.
GGT Blood Test UK
The marker that separates a liver source from a bone one.
Liver Function Test UK
How the panel works as a set rather than five lines.
Vitamin D Deficiency UK
The most likely explanation, and how it is measured.
Bone Health Blood Results Explained
What calcium, phosphate and vitamin D each add.
Related panels
Keep reading