An alkaline phosphatase (ALP) test measures the amount
of the
enzyme ALP in the blood. ALP is made mostly in the
liver and in bone with some made in the
intestines and
kidneys. It also is made by the
placenta of a pregnant woman.
The liver
makes more ALP than the other organs or the bones. Some conditions cause large
amounts of ALP in the blood. These conditions include rapid bone growth (during
puberty), bone disease (osteomalacia or
Paget's disease), or a disease that affects how much
calcium is in the blood (hyperparathyroidism), or damaged liver cells.
If the ALP level is high, more tests may be done to find the
cause.
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, osteomalacia, 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 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.
If you are having a follow-up
ALP test, you may be asked to not eat or drink for 10 hours before the test.
The ALP level generally goes up after eating, especially after eating fatty
foods.
Many medicines may change the results of this test. Be sure
to tell your doctor about all the
nonprescription and prescription medicines you
take.
Talk to your doctor about any concerns you have regarding the
need for the test, its risks, how it will be done, or what the results will
mean. To help you understand the importance of this test, fill out the
medical test information form(What is a PDF document?).
Wrap an elastic band around your upper arm to
stop the flow of blood. This makes the veins below the band larger so it is
easier to put a needle into the vein.
Clean the needle site with
alcohol.
Put the needle into the vein. More than one needle stick
may be needed.
Attach a tube to the needle to fill it with
blood.
Remove the band from your arm when enough blood is
collected.
Put a gauze pad or cotton ball over the needle site as
the needle is removed.
The blood sample is taken from a vein in
your arm. An elastic band is wrapped around your upper arm. It may feel tight.
You may feel nothing at all from the needle, or you may feel a quick sting or
pinch.
There is very little chance of a problem from
having blood sample taken from a vein.
You may get a small bruise at the site. You can
lower the chance of bruising by keeping pressure on the site for several
minutes.
In rare cases, the vein may become swollen after the blood
sample is taken. This problem is called phlebitis. A warm compress can be used
several times a day to treat this.
Ongoing bleeding can be a
problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and
other blood-thinning medicines can make bleeding more likely. If you have
bleeding or clotting problems, or if you take blood-thinning medicine, tell
your doctor before your blood sample is taken.
Women in the third
trimester of pregnancy have high ALP levels because
the
placenta makes ALP. Children normally have much higher
ALP than adults because rapid bone growth is normal in children and bones make
ALP.
High values
Very high levels of ALP can be caused by
liver problems, such as
hepatitis, blockage of the bile ducts (obstructive
jaundice),
gallstones,
cirrhosis, liver cancer, or cancer that has spread
(metastasized) to the liver from another part of the body.
High
ALP levels can be caused by bone diseases, such as
Paget's disease,
osteomalacia,
rickets, bone tumors, or tumors that have spread from
another part of the body to the bone, or by overactive
parathyroid glands (hyperparathyroidism). Normal
healing of a bone fracture can also raise ALP levels.
Conditions that lead to malnutrition
(such as
celiac disease) or are caused by a lack of nutrients
in the diet (such as
scurvy) can cause low ALP levels.
If the ALP level is high, other tests may be
done to determine whether a liver or bone problem is present.
If liver disease is suspected, more blood tests, an
ultrasound, or a
CT scan are generally recommended to find the
problem.
Other tests to check liver function, such as alanine
aminotransferase, aspartate aminotransferase, and bilirubin, are often done at
the same time as an alkaline phosphatase (ALP) test. For more information, see
the medical tests
Alanine Aminotransferase (ALT),
Aspartate Aminotransferase (AST), and
Bilirubin.
Gamma glutamyl transferase
(GGT), or gamma glutamyl transpeptidase, may be measured in the blood to check
the difference between bone ALP and liver ALP. High levels of GGT are present
when the liver is damaged but not present with bone disease. A high level of
GGT may be caused by alcohol use or may mean that blocked bile ducts are
causing inflammation. The level of GGT may be high with the use of certain
medicines, such as phenytoin and phenobarbital. In some medical centers, a test
that measures a substance called 5-nucleotidase is done instead of the GGT test
because it is better at finding liver disease.
This information does not replace the advice of a doctor. Healthwise disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.This information does not replace the advice of a doctor. Healthwise disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.
