Patient education: Alkaline phosphatase test (The Basics)

What is an alkaline phosphatase test? — 

This is a blood test that can show if there are problems in the liver or bones. It measures the level of a substance called alkaline phosphatase, or "ALP," in the blood.

ALP is an "enzyme." These help keep the body working normally. Most ALP is made in the liver and bones. But low levels of ALP can also be found in many other parts of the body.

If there is a problem with the liver or bones, the body might make too much ALP. This can also happen if you have gallstones or something else that blocks the flow of bile. (The gallbladder is under the liver. It normally fills with bile between meals, then empties into the intestine.)

Other things can also cause a high ALP level. Some are health problems, and some are temporary conditions like pregnancy or healing after a broken bone.

Why might I need an alkaline phosphatase test? — 

Your doctor might order this test:

●To help diagnose a liver or gallbladder problem

●To check for problems with bones

●To check how well treatment is working, if you were already diagnosed with a problem

●As part of a routine check-up

How do I prepare for an alkaline phosphatase test? — 

You need to get a "blood draw." Your doctor or nurse will tell you where to go for this.

It might help to wear a short-sleeve shirt to your blood draw appointment. This makes it easier for the person drawing your blood to get to your arm.

What happens during a blood draw? — 

A needle is used to take a small amount of blood from your arm (figure 1). Collecting the blood only takes a few minutes. The blood is then tested in a lab.

Tell the person who takes your blood:

●If you take "blood thinner" medicines or if you have a bleeding problem – They will make sure your bleeding is under control before you leave.

●If you have a latex allergy – Some of the supplies used for blood draws might contain latex.

●If you have a preferred arm to use

Most of the time, getting blood taken does not cause problems. You might have a little soreness or bruising where the needle went in.

What do my results mean? — 

Your doctor or nurse will tell you when to expect your results, and will contact you with the results. Or if you use an online "patient portal," you might get an alert there when your results are ready.

If the test shows your ALP is high, your doctor or nurse will talk to you about what to do next. They might need to do more tests to figure out the cause.

If you do have a health problem, your doctor will work with you to come up with a plan for treatment.

More on this topic

Patient education: Comprehensive metabolic panel (The Basics)
Patient education: Liver panel (The Basics)
Patient education: Gallstones (The Basics)
Patient education: Primary biliary cholangitis (The Basics)
Patient education: Paget disease of bone (The Basics)

Patient education: Gallstones (Beyond the Basics)
Patient education: Paget disease of bone (osteitis deformans) (Beyond the Basics)