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Hemochromatosis Gene Test (HFE Test)
Test Overview
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. However, 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.
Why It Is Done
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.
How To Prepare
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
indicate. To help you understand the importance of this test, fill out the
medical test
information form
(What is a PDF document?)
.
How It Is Done
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.
How It Feels
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.
Risks
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.
Results
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. Results are usually available in 1 to 2 weeks.
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.
|
What Affects the Test
The results of a hemochromatosis gene test may not be accurate if
you have had a blood transfusion done within a week of the test.
What To Think About
- 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. Ask your doctor who else might see your results to make sure your
information remains private.
- 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.1
- 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.
References
Citations
-
National Human Genome Research Institute (2005).
Learning about hereditary hemochromatosis. Available online:
http://www.genome.gov/page.cfm?pageID=10001214.
Other Works Consulted
-
Chernecky CC, Berger BJ, eds. (2004). Laboratory Tests and Diagnostic Procedures, 4th ed.
Philadelphia: Saunders.
-
Fischbach FT, Dunning MB III, eds. (2004).
Manual of Laboratory and Diagnostic Tests, 7th ed.
Philadelphia: Lippincott Williams and Wilkins.
-
Pagana KD, Pagana TJ (2006). Mosby’s
Manual of Diagnostic and Laboratory Tests, 3rd ed. St. Louis:
Mosby.
Credits
| Author | Jan Nissl, RN, BS |
| Editor | Susan Van Houten, RN, BSN, MBA |
| Associate Editor | Tracy Landauer |
| Primary Medical Reviewer | Anne C. Poinier, MD - Internal Medicine |
| Specialist Medical Reviewer | Brian Leber, MDCM, FRCPC - Hematology |
| Last Updated | April 30, 2007 |
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| Author: | Jan Nissl, RN, BS | Last Updated: April 30, 2007 |
| Medical Review: | Anne C. Poinier, MD - Internal Medicine
Brian Leber, MDCM, FRCPC - Hematology |
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