Alkaline Phosphatase
Results
An alkaline phosphatase (ALP) test measures the amount of the enzyme ALP in the blood.
Normal
Normal values may vary from lab to lab.
Alkaline phosphatase Adults: 30–126 units per liter (U/L) or 0.5–2.0 microkat/liter (mckat/L)
Children: 30–300 U/L or 0.5–5.0 mckat/L
Women in the third trimester of pregnancy have high ALP levels because the placenta makes ALP. Children normally have much higher ALP than adults because rapid bone growth is normal in children and bones make ALP.
High values
- Very high levels of ALP can be caused by liver problems, such as hepatitis, blockage of the bile ducts (obstructive jaundice), gallstones, cirrhosis, liver cancer, or cancer that has spread (metastasized) to the liver from another part of the body.
- High ALP levels can be caused by bone diseases, such as Paget's disease, osteomalacia, rickets, bone tumors, or tumors that have spread from another part of the body to the bone, or by overactive parathyroid glands (hyperparathyroidism). Normal healing of a bone fracture can also raise ALP levels.
- Heart failure, heart attack, mononucleosis, or kidney cancer can raise ALP levels. A serious infection that has spread through the body (sepsis) can also raise ALP levels.
Low values
Conditions that lead to malnutrition (such as celiac disease) or are caused by a lack of nutrients in the diet (such as scurvy) can cause low ALP levels.
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| Author: | Caroline Rea, RN, BS, MS | Last Updated: July 28, 2008 |
| Medical Review: | Caroline S. Rhoads, MD - Internal Medicine Alan C. Dalkin, MD - Endocrinology | |
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| Topic Contents | |
| Test Overview | |
| Why It Is Done | |
| How To Prepare | |
| How It Is Done | |
| How It Feels | |
| Risks | |
 | Results |
| What Affects the Test | |
| What To Think About | |
| References | |
| Credits | |