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November 17, 2021 | Farah Jassawalla

What Does High Alkaline Phosphatase Indicate?

What is Alkaline Phosphatase?

Alkaline phosphatase is also known as ALP. It is an enzyme found in the bloodstream. Alkaline phosphatase helps in the breakdown of proteins in the body. The enzyme exists in various forms throughout the body with the liver being one of the main sources of ALP. Other parts of the body where alkaline phosphatase is formed include the bones, kidneys, intestines, and pancreas. In pregnant women, ALP is made in the placenta as well. 

The exact function of ALP is not yet fully understood by scientists, however, it is believed to be important for multiple processes in the body. In particular, it is believed to play an important role in the functioning of the liver and bone development.

Abnormal levels of ALP in the blood are indicative of health concerns with either the liver, bones, or gallbladder. However, abnormal levels of alkaline phosphatase can also indicate kidney cancer tumors, intestinal concerns, pancreas concerns, infections, and malnutrition. 

The normal level of ALP in the body varies from person to person. The level is dependent on age, gender, blood type, and whether or not the person is pregnant. In general, the normal range is higher in children and decreases with age. The best way to assess whether your ALP levels are normal or not is to discuss the results of your test with the doctor who will use the lab which conducted your test’s specific result and reference ranges.

The levels of ALP in the body are tested with an alkaline phosphatase blood test. The blood test is a simple procedure that involves drawing blood from a vein in your arm using a syringe and sending the sample to the lab for testing. The results will indicate whether you have low alkaline phosphatase or high alkaline phosphatase or whether your results are normal. 

Why is an Alkaline Phosphatase blood test ordered?

The doctor may order a blood test panel which includes an ALP test if a patient has symptoms of liver problems, such as:

The test is specifically ordered for conditions affecting kidneys, bones, intestines, and gallbladder. 

What do the results mean?

High alkaline phosphatase indicates that there is damage to the liver or that the patient has some type of bone disorder. When the liver is damaged, it creates a different form of ALP from the one which is formed when there is a bone disorder. If the test results indicate that alkaline phosphatase levels are high, the doctor will order a range of other additional tests to gauge where the ALP is being formed. High levels of alkaline phosphatase can indicate a variety of problems with the liver, such as cirrhosis, hepatitis, a blockage in the bile duct, or mononucleosis, which can lead to swelling in the liver. It can also be indicative of overuse of medications harmful to the liver and excessive consumption of alcohol

Additional tests are used to find out which type of ALP enzyme is high in the blood. Different parts of the body make different ALP enzymes. Tests that check liver function include bilirubin, aspartate aminotransferase (AST), and alanine aminotransferase tests. If the results of these tests are normal, despite the levels of ALP being high, the problem is not in the liver. 

In this case, high ALP levels are indicative of bone disorders like rickets, bone cancer, and Paget’s disease - a condition in which the bones are abnormally large and weak, and can be easily fractured. Sometimes, high levels of ALP can indicate kidney cancer, other cancers, heart failure, or a bacterial infection - but this is rare. 

The treatment of high levels of ALP is dependent on the diagnosis. People who have liver, gallbladder, or bone obstructions might have to get surgery, or laser therapy sessions to break down the obstructions. They may also be put on meds. Patients with cancer will have to opt for a combination of chemo, radiotherapy, and surgery. 

Low levels of alkaline phosphatase may indicate hypophosphatasia which is a rare genetic disease that affects the bones and teeth. However, low levels of ALP can also be caused by a deficiency of zinc in the body or malnutrition. In the case of the latter, treatment includes adjusting the diet accordingly and taking supplements. It is recommended to take whole foods like whole-grain cereals, rice, bread, whole fruits and vegetables, red meats, and fatty fish as well as probiotic foods like yogurt and kimchi.

Unusual levels of ALP can rarely indicate the following as well:

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Farah Jassawalla

Farah Jassawalla is a graduate of the Lahore School of Economics. She is also a writer, and a healthcare enthusiast, having closely observed case studies while working with Lahore's thriving general physicians at their clinics.