If the ALP level is high, more tests may be done to find the cause. The amounts of different types of ALP in the blood may be measured and used to determine whether a high level is from the liver or bones. This is called an alkaline phosphatase isoenzymes test.
A test for alkaline phosphatase (ALP) is done to:
- Check for liver disease or damage to the liver. Symptoms of liver disease can include jaundice, belly pain, nausea, and vomiting. An ALP test may also be used to check the liver when medicines that can damage the liver are taken.
- Check bone problems (sometimes found on X-rays), such as rickets, bone tumors, Paget's disease, or too much of the hormone that controls bone growth (parathyroid hormone). The ALP level can be used to check how well treatment for Paget's disease or a vitamin D deficiency is working. An alkaline phosphatase test is often done at the same time as a routine blood test. You do not need to do anything before having a routine blood test.
An alkaline phosphatase (ALP) test measures the amount of the enzyme ALP in the blood.
- High values
High ALP levels can be caused by bone diseases, such as Paget's disease, osteomalacia, rickets, bone tumours, or tumours that have spread from another part of the body to the bone, or by over-active parathyroid glands (hyperthyroidism). 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. Women in the third trimester of pregnancy have high ALP levels because the placenta makes ALP.
- Low values
In addition, an increase of 2 to 3 times normal may be observed in women in the third trimester of pregnancy, although the interval is very wide and levels may not exceed the upper limit of the reference interval in some cases. The additional enzyme is of placental origin. Pediatric reference values should be used to properly interpret alkaline phosphatase values in children and adolescents