Hemochromatosis
gene (HFE) testing is a blood test used to check for hereditary
hemochromatosis, an inherited disorder that causes the body to absorb too much
iron. The iron then builds up in the blood, liver, heart, pancreas, joints,
skin, and other organs.
In its early stages, hemochromatosis can
cause joint and belly pain, weakness, lack of energy, and weight loss. It can
also cause scarring of the liver (cirrhosis),
darkening of the skin,
diabetes,
infertility,
heart failure, irregular heartbeats (arrhythmia), and
arthritis. But many people do not have symptoms in the
early stages.
In men, hereditary hemochromatosis is usually found
between the ages of 40 and 60. In women, it is not usually found until after
menopause because, until that time, women regularly
lose blood and iron during their monthly periods.
HFE testing is used to find out if a
person has an increased chance of having hemochromatosis. It is often
recommended for people who have a close family member—parent, brother, sister,
or child—with this disease.
HFE testing locates and identifies
common mutations in the HFE gene. It is used to find out if a person has an
increased chance of having hemochromatosis. You may decide to have HFE
testing:
If other people in your family have
hemochromatosis and you want to see if you carry a mutation and might pass the
disease on to your children. Information from screening can help you make
decisions about your health care.
If two separate blood tests,
which include a ferritin level and transferrin saturation, are done and they
show that you have high iron levels in your blood (iron overload). More than
half of people with iron overload have HFE gene mutations.
To find out whether you have hemochromatosis before you develop
related problems, such as liver disease. Early treatment can help prevent later
problems. Treatment can be as simple as routinely removing blood, in the same
way as blood is removed when you donate blood. This brings iron levels
down.
Generally, no special preparation is
required before having a hemochromatosis gene test.
Genetic test
results often have
ethical, legal, or social implications. You may want
to talk to a
genetic counselor before making a decision about
testing. Genetic counselors are trained to explain the test and its results
clearly. A genetic counselor can help you make well-informed decisions.
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?).
The health professional taking a sample
of your blood will:
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.
Put pressure on the site and then put on a
bandage.
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.
You may worry or feel nervous before you have the test or
while you are waiting for the results.
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.
Hemochromatosis gene (HFE) testing is a
blood test used to check for hereditary hemochromatosis, a disorder that is
passed from a parent to a child (inherited) and causes the body to absorb too
much iron. This HFE gene test is usually not used to check for other, less
common causes of inherited hemochromatosis.
Hemochromatosis gene (HFE)
Normal:
No mutations are found in the HFE gene.
Normal results are called negative.
Abnormal:
Mutations are found in the HFE gene test.
Abnormal results are called positive.
An abnormal test result does not mean that you have
hemochromatosis or that you will have hemochromatosis. It means that you have a
mutation in the HFE gene. Ask your doctor or a
genetic counselor to help you understand your test
results.
If you are thinking about having genetic testing, talk with your
doctor about the benefits as well as the possibility of insurance, employment,
or other discrimination based on test results. An HFE test result is private
information.
The information obtained from an HFE test can have a big impact
on your life. Genetic counselors are trained to help you understand your chance
for having a child with an inherited (genetic) disease. A genetic counselor can
help you make well-informed decisions. Ask to have genetic counseling before
making a decision about HFE testing.
HFE testing is not able to
predict whether you will have hemochromatosis. Although the test locates the
most common HFE mutations, there may be other HFE mutations that the test does
not find. You may have HFE mutations and not have the diseases or you may have
symptoms of the disease but gene testing is does not find any mutations.
HFE gene testing may identify the cause of high iron levels and
eliminate the need for other tests, such as a
liver biopsy.
Iron and ferritin levels may
also be checked at the same time as a hemochromatosis gene test. For more
information, see the medical tests
Iron and
Ferritin.
Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis:
Saunders.
Fischbach FT, Dunning MB III, eds. (2009).
Manual of Laboratory and Diagnostic Tests, 8th ed.
Philadelphia: Lippincott Williams and Wilkins.
National Human Genome Research Institute (2008). Learning about hereditary hemochromatosis. Available online: http://www.genome.gov/page.cfm?pageID=10001214.
Qaseem A, et al. (2005). Screening for hereditary
hemochromatosis: A clinical practice guideline from the American College of
Physicians. Annals of Internal Medicine, 143(7):
517–521.
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