Alkaline phosphatase (ALP) is an enzyme found mainly in the liver's bile ducts and in bone.
- Normal range (adults)
- Men 44–147 U/L · Women 35–104 U/L
- Sample
- Blood
- Fasting
- Not usually needed
- Also called
- ALP, Alk Phos, Alkaline Phosphatase, Alk Phosphatase, ALKP
Alkaline Phosphatase normal range
| Group | U/LSame unit in all countries |
|---|---|
| Men | 44–147 |
| Women | 35–104 |
ALP is normally much higher in children and teenagers because their bones are growing.
Ranges vary slightly between laboratories. The range printed on your own report is the one to go by.
Why is the Alkaline Phosphatase test done?
It is part of the liver function test and helps detect blocked bile ducts and bone disorders.
What does a high Alkaline Phosphatase level mean?
A high ALP points to a problem with bile flow from the liver, or to increased bone activity. It is normally high in growing children and in pregnancy.
Common causes
- Gallstones or blockage of the bile ducts
- Liver disease affecting the bile ducts
- Vitamin D deficiency and bone softening
- Healing fractures and growing bones in children
- Pregnancy (from the placenta)
- Paget's disease of bone or an overactive parathyroid
Diet and lifestyle tips
- If vitamin D is low: sunlight, oily fish, egg yolks and fortified foods
- Eat calcium sources: milk, yogurt, cheese, sesame, leafy greens
- For bile problems: smaller, lower-fat meals and less fried food
- Avoid alcohol
What does a low Alkaline Phosphatase level mean?
A low ALP is uncommon.
Common causes
- Zinc or magnesium deficiency
- Malnutrition
- Underactive thyroid
- Rare inherited hypophosphatasia
Diet and lifestyle tips
- Eat zinc sources: meat, seeds, nuts, legumes
- Eat magnesium sources: nuts, whole grains, leafy greens
When should you see a doctor?
A high ALP with high GGT points to the liver; with normal GGT, to bone. Your doctor will decide what further tests are needed.
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This page is for general education and is not a diagnosis. Normal ranges differ between laboratories, so always compare your result with the reference range printed on your own report, and discuss abnormal results with your doctor.