Is my ALP (Alkaline Phosphatase) normal?
Free blood test checker · Standard + longevity-optimal ranges
What is a normal ALP level?
ALP is an enzyme with dual sources: liver and bone. Optimal functional range is 45-100 U/L (standard normal 44-147 U/L). Elevated ALP with normal GGT suggests bone origin (growth in children, Paget's disease, vitamin D deficiency). Elevated ALP with elevated GGT suggests biliary or liver origin (cholestasis, bile duct obstruction). This liver-vs-bone distinction makes GGT an essential companion test when ALP is elevated.
| Range | Values |
|---|---|
| Standard Reference | 44–147 U/L |
| High Risk | > 200 U/L |
What causes abnormal ALP levels?
Elevated ALP is caused by bile duct obstruction (gallstones, tumors), cholangitis, hepatitis (viral, alcoholic, autoimmune), cirrhosis, Paget's disease of bone, bone metastases, fracture healing, hyperparathyroidism, vitamin D deficiency (compensatory bone turnover), pregnancy (placental isoenzyme), and hyperthyroidism. Low ALP can occur in hypothyroidism, zinc deficiency, and rare genetic conditions (hypophosphatasia).
When should you see a doctor?
See your doctor if ALP is above 147 U/L, especially with symptoms like jaundice, dark urine, pale stools, abdominal pain, or bone pain. ALP above 200 U/L is critical and warrants urgent evaluation. If ALP is isolated (normal GGT, ALT, AST), bone evaluation should be considered.
ALP and longevity
ALP is a useful but nonspecific marker that reflects both hepatobiliary and skeletal health. In the context of aging, persistently elevated ALP may indicate subclinical vitamin D deficiency (compensatory osteoblast activity), fatty liver disease progression, or occult bone pathology. Low ALP is emerging as a marker of interest in longevity research — hypophosphatasia and zinc deficiency can impair bone mineralization. Comprehensive liver panels (ALT, AST, GGT, ALP, bilirubin, albumin) provide the most informative picture of hepatic health.
Where to get a ALP test
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Related biomarkers
These biomarkers are often tested alongside ALP for a more complete picture.
Frequently asked questions
What is a normal ALP level?
How do I tell if high ALP is from the liver or bone?
What causes elevated ALP?
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Sources: Reference ranges based on AHA/ACC, ADA, and AACE clinical guidelines. Biological variation data from Ricos/Westgard database. Longevity-optimal ranges reflect targets used by preventive and functional medicine practitioners.
Last reviewed: April 2026. This tool provides general health information and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult your healthcare provider about your specific results.