A number of conditions may cause high alkaline phosphatase in the blood, such as serious infection, liver problems or bone issues, states WebMD. Heart attack, mononucleosis, heart failure, kidney cancer or being in the third trimester of pregnancy can also cause elevated ALP levels.
Alkaline phosphatase is a protein that exists in each of the body's tissues but is mostly found in the liver, bones and bile ducts, indicates MedlinePlus. The normal range of ALP for adults is 25 to 100 units per liter, although reference ranges may vary from lab to lab, according to WebMD. Very high levels of ALP may be the result of liver problems, such as jaundice, gallstones, hepatitis, liver cancer or cirrhosis. High levels of ALP can be caused by healing of a bone fracture, overactive thyroid glands, or bone diseases, such as rickets, Paget's disease or osteomalacia. Tumors in a bone or tumors which spread from another part of the body to the bone may also cause higher than normal ALP levels.
Other conditions related to elevated ALP levels include sarcoidosis, bilary obstruction, leukemia or lymphoma, states MedlinePlus. Individuals with type B or type O blood may also experience raised ALP levels as a result of eating a fatty meal.