TL;DR: An ALP blood test measures alkaline phosphatase, an enzyme found especially in the liver, bile ducts and bones, but the test alone cannot identify where the ALP came from. MedlinePlus
Key takeaways
- Alkaline phosphatase, or ALP, is an enzyme, a protein that speeds up chemical reactions. MedlinePlus
- ALP appears in liver and calcium profiles at Royal United Hospitals Bath; panel names do not replace checking the actual tests on your report. NHS laboratory guidance
- A high ALP result does not identify its source, and other tests may be needed. MedlinePlus
- Age and pregnancy can affect ALP, so a number needs the relevant clinical context. MedlinePlus
- Ask a healthcare professional to explain unclear results and what happens next. NHS
What does an ALP blood test measure?
An ALP blood test measures alkaline phosphatase in the blood. ALP is found throughout the body's tissues, with higher amounts in the liver, bile ducts and bones; different parts of the body make different types. MedlinePlus
The important distinction is between measuring ALP and establishing its source. MedlinePlus says the test alone cannot identify that source, so further tests are usually needed to make a diagnosis. Source
The abbreviation is pleasingly short. The explanation has declined to be quite so obliging.
Why does ALP appear alongside liver tests?
ALP can be included in a liver profile, but it is not exclusively a liver measurement. Royal United Hospitals Bath describes ALP as part of liver function and calcium profiles, while North West London Pathology lists both bone pain and suspected liver impairment among its clinical indications. Bath laboratory guidance North West London Pathology
That explains why the panel heading is not enough to interpret the number. Those pages describe clinical laboratory uses of ALP, not the capabilities or clinical utility of MeScreen.
For related test literacy, read our bilirubin guide and albumin guide. Keep the discussion of your own panel with the healthcare professional who requested it.
Does high ALP automatically mean liver disease?
No, a high ALP result does not automatically establish liver disease. MedlinePlus says high levels may relate to liver or bone problems, but the ALP result cannot tell which type is high; it is also possible to have a higher level without a condition needing treatment. Source
The practical point is not to choose a diagnosis from a list of possibilities. MedlinePlus says the healthcare provider considers symptoms, medical history and other test results. Source
A flag on a report is a prompt for context. It is not the entire clinical plot in fluorescent stationery.
Why might GGT be discussed with ALP?
Gamma-glutamyl transferase, usually shortened to GGT, is another enzyme measured in a blood test. MedlinePlus GGT may help a clinician investigate the source of raised ALP, but Bath's laboratory guidance cautions that elevated GGT does not necessarily establish a liver origin for raised ALP. Bath laboratory guidance
That qualification matters. This article is not a formula for combining two results into a diagnosis, nor a recommendation to order tests yourself. Ask the requesting clinician how the whole set of findings fits together.
Which reference range should you look at?
Look at the age-appropriate range on the actual report rather than importing a threshold from somebody else's laboratory page. Bath says its quoted adult range applies from age 19 and directs readers to the report or laboratory for age-specific and sex-specific ranges. Source
MedlinePlus notes that pregnancy can raise ALP and that children and teenagers may have higher levels because their bones are growing. These are reasons to retain context, not reasons for this article to interpret a person's result. Source
Keep the test name, unit, local range and reason for testing together when discussing the report. The NHS advises asking a healthcare professional when results are unclear. Source
What should you ask your healthcare team?
Ask why ALP was measured, how it relates to the other findings and what the agreed next step is. The NHS says the GP, nurse or specialist should explain the results and what happens next. Source
Useful discussion prompts include whether more information is needed, who will arrange any follow-up and when you should expect to hear back. This article does not recommend changes to medicines, supplements, diet, fasting or fluid intake. For preparation, the NHS says the requesting professional should tell you what is needed. Source
Where does mescreen™ fit?
mescreen™'s current UK page describes the service as a wellness and functional laboratory assessment for informational purposes, not a medical diagnostic test. mescreen™ UK
This article does not establish that mescreen™ measures ALP, investigates an abnormal ALP result or identifies liver or bone disease. Read the current service information if you are considering mescreen™, and take questions about clinical blood-test results to your healthcare professional.
Limitations
This article cannot interpret an individual's result, establish its cause or recommend treatment. It does not show that an in-range result rules out illness, and it does not claim a diagnostic or health-outcome benefit for MeScreen. Images are generated editorial illustrations, not actual results, samples, mescreen™ facilities or validated equipment.
Sources
- MedlinePlus, National Library of Medicine, Alkaline Phosphatase: https://medlineplus.gov/lab-tests/alkaline-phosphatase/
- MedlinePlus, National Library of Medicine, Gamma-glutamyl Transferase (GGT) Test: https://www.medlineplus.gov/lab-tests/gamma-glutamyl-transferase-ggt-test/
- Royal United Hospitals Bath NHS Foundation Trust, Alkaline Phosphatase, laboratory content updated February 2026: https://ruh.nhs.uk/pathology/blood_test_info/tubelisting.asp?id=21&listing=a
- North West London Pathology, Alkaline phosphatase (ALP): https://www.nwlpathology.nhs.uk/test/alkaline-phosphatase-alp/
- NHS, Blood tests, reviewed 2 November 2023: https://www.nhs.uk/tests-and-treatments/blood-tests/
- mescreen™ UK, current service and non-diagnostic boundary: https://mescreen.co.uk/