Alkaline Phosphatase
Also written as: ALP, alk phos
An enzyme from the liver, bile ducts, and bone, used to screen for bile flow and bone turnover activity.
What it measures
The activity of alkaline phosphatase, an enzyme found mainly in the liver and bile ducts and in bone, with smaller amounts from the intestine and, during pregnancy, the placenta. The blood level reflects how much is being released from these tissues.
Why a doctor orders it
It is a standard part of liver panels and is used to screen for problems with bile flow and for conditions of increased bone activity. Because it comes from more than one organ, an elevated result often leads to further tests to identify the source.
What is generally associated with a higher result
Broadly associated with conditions affecting the bile ducts and with increased bone turnover, such as healing fractures or bone conditions. It is also normally higher in growing children and teenagers and during the later stages of pregnancy, and can rise after a fatty meal in some people.
What is generally associated with a lower result
Broadly associated with malnutrition, low zinc or magnesium, and some rare inherited conditions. Low values are generally not pursued.
Everyday things that move this number
Not every shift in a value reflects disease. These are ordinary factors known to affect this particular measurement:
- Pregnancy, which normally raises it
- Age - it is naturally high in growing children and adolescents
- A recent or healing broken bone
- Eating a fatty meal shortly before a non-fasting draw
- Some common medications
Questions to take to your appointment
- Could a GGT test help show whether this is coming from the liver or from bone?
- Could pregnancy, growth, or a recent fracture explain the level?
- Should vitamin D and bone health be looked at alongside this?
Build a printable questionnaire with your own results →
Where to read more
MedlinePlus, from the US National Library of Medicine, publishes patient-facing pages on individual lab tests and is a reliable next stop: medlineplus.gov/lab-tests .
Support this site
This site is free, has no paywall, and takes no money from hospitals, insurers, or billing companies. If it helped, a coffee keeps it going.
Buy us a coffee