Alkaline Phosphatase (ALP) Test - Normal Value, Procedure, Levels Preparation and Result

The enzyme alkaline phosphatase is found all over your body, primarily in the liver, bones, kidneys, and intestines. An alkaline phosphatase test is usually used to measure the levels of ALP from the bones and liver in the blood. Although alkaline phosphatase can be tested by itself, it is a test found in the comprehensive metabolic panel. Abnormally high alkaline phosphatase levels could indicate bone or liver conditions.

What is the Purpose of an Alkaline Phosphatase Level Test?

There are two primary purposes of an alkaline phosphatase test to identify issues with the,

Liver and Gallbladder

Here the alkaline phosphatase levels in the blood are checked as a part of the routine liver function and gallbladder. A doctor may prescribe a serum alkaline phosphatase blood test if you have nausea, vomiting, abdominal pain, and jaundice symptoms. This test helps to identify conditions like

• Blockages in the bile duct
• Inflammation of the gallbladder
• Liver scarring
• Inflammation of the liver caused by some forms of hepatitis

Sometimes you may also need to take a serum alkaline phosphatase test if you have been taking medicines like acetaminophen that are potentially harmful to the liver.

Bones

A serum alkaline phosphatase test helps identify bone conditions such as

• Rickets: The softening and weakening of bones in children can be caused due to the lack of vitamin D or calcium.
• Osteomalacia: This is a condition in adults where the bones soften due to a lack of Vitamin D or the body’s ability to process Vitamin D.
• Paget’s Disease: This is a serious concern related to the destruction and regrowth of bones.

Another case in which a serum alkaline phosphatase blood test may be recommended is to investigate the presence of cancerous tumours, any unusual growth of bones, or deficiency in Vitamin D. It can also be used to track the progression of the treatment of the diseases mentioned above.

How does a Serum Alkaline Phosphatase Test Differ From a Liver Function Test or a Comprehensive Metabolic Panel?

A panel blood test is one in which multiple parameters are tested using a single blood sample. While a single parameter test like serum alkaline phosphatase could help identify specific disorders, most doctors may suggest you carry out a complete series of tests that includes measuring all liver enzymes that can help get a complete picture of how healthy the liver is.

How is the Serum Alkaline Phosphatase Test Done?

• A lab technician or phlebotomist will draw a small amount of blood to perform the test. They usually place a tight elastic band known as a tourniquet around your upper arm. This tourniquet makes the veins swell with blood.
• They will then clean the area of the skin from where the blood is to be drawn with rectified spirit to sterilize the area. This spot is usually the inside of the elbow or at the back of your hand. There will be a slight prick when the needle penetrates the skin, and then you will be able to see the blood flow into the small vial (vacutainer) that is attached to the needle.
• Once the blood is collected, the lab tech will take off the tourniquet and put a small bandage where the needle penetrates the skin.
• The sample will then be sent to a lab where a pathologist will prepare the sample and perform the test on a machine known as an analyser.
• The turnover time for the test will depend on how fast your doctor needs the results; however, you should get the results of your serum alkaline phosphatase test within a day or two of the sample collection.

Preparing For your Serum Alkaline Phosphatase Test

If this test is part of a comprehensive metabolic panel of tests, you may have to fast or limit your intake of liquids and solids for 10 to 12 hours before the test.

Some medicines may also affect the results of the test, in which case you will need to keep your doctor informed about any drugs you take, including vitamins, supplements, and any over-the-counter medications.

You should also inform your doctor if you are pregnant, as that can increase alkaline phosphatase levels in your blood.

Your doctor should give you all the required precautions before the serum alkaline phosphatase blood test; if they haven’t, you can always ask the diagnostic centre conducting the test for any special precautions.

What Do Your Results Mean?

Like all tests, serum alkaline phosphatase test results are divided into high, normal, and low levels. While serum alkaline phosphatase normal values are usually good news, let’s look at the other two effects.

High levels

Results showing higher-than-normal levels of alkaline phosphatase in the blood may indicate health concerns regarding your gallbladder and liver. In rare cases, high levels of alkaline phosphatase could also indicate kidney cancer, heart failure, mononucleosis, other cancers, or bacterial infections.

Low levels

This is usually a sign that your blood shows a protein deficiency or, in some cases, Wilson’s disease. It could also indicate malnutrition caused by celiac disease or insufficient amounts of minerals and vitamins in your diet.

If your results are high or low, your doctor will advise you on your next steps. In the case of mild elevations, your doctor may wait a while and test again to check if your levels have returned to normal. If your doctor has cause for concern, they may prescribe other tests, such as

• Isoenzyme tests
• Vitamin and mineral levels
• Organ function tests
• Diagnostic imaging of the liver and gallbladder

Risks of the Serum Alkaline Phosphatase Test

Drawing blood for the test is risk-free; the only risk is minor bruising around the puncture site. In rare cases, an inflammation of the vein may occur that can be reduced with a warm compress. However, you must inform your doctor if you have taken any blood thinners or have a bleeding disorder.

Takeaway

A serum alkaline phosphatase test is simple to perform and only requires a blood draw. These tests are usually accurate and can be delivered within a few days. At Metropolis Healthcare, we conduct these and more diagnostic tests with our clients’ convenience being our utmost priority.