Alkaline phosphatase is an enzyme found in many organs, including the liver, bone, kidney, intestine and placenta.
The highest concentration of alkaline phosphatase comes from the liver and bone. A routine blood test detects the total amount of alkaline phosphatase in the blood.
Normal Values. The normal value for alkaline phosphatase is 53 to 128 U/L for a 20- to 50-year-old man and 42 to 98 U/L for a 20- to 50-year-old woman. Pregnant women typically have higher alkaline phosphatase values due to contributions from the placenta. Normal values are slightly different if you are older than 60 — 56 to 119 U/L if you’re a man or 53 to 141 U/L if you’re a woman.
High levels. Higher than normal levels of ALP in your blood may indicate a problem with your liver or gall bladder. This could include hepatitis (infection), cirrhosis (scarring), liver cancer, gallstones, or a blockage in your bile ducts. High levels may also indicate an issue related to the bones such as rickets, Paget’s disease, bone cancer, or an overactive parathyroid gland. In rare cases, high ALP levels can indicate heart failure, kidney cancer, mononucleosis, or a blood infection.
Low levels. Lower than normal ALP levels in your blood is rare, but can indicate malnutrition, which could be caused by celiac disease or a deficiency in vitamins and minerals.
An ALP test may be performed to determine how well your liver and gallbladder are functioning.
Eating can interfere with your ALP levels. You may be asked to fast before the test.
The test requires a health professional to draw a small sample of blood from your arm.