Does this test have other names?
Alpha-1-antiprotease deficiency, alpha-1-antiproteinase inhibitor deficiency, AAT
deficiency, alpha-1-antitrypsin (A-1AT) deficiency
What is this test?
This is a blood test to help find out if liver disorders and lung diseases such as
emphysema are caused by a genetic disorder called alpha-1antitrypsin deficiency. This
is especially true if they show up much earlier than they normally would. This disorder
is linked to abnormally low levels or a lack of alpha-1 antitrypsin (AAT) protein
in the blood.
AAT is a protein made in the liver that helps your lungs work normally. The test finds
out whether you have normal or damaged copies of a gene that makes this protein. If
you have AAT deficiency, you have two damaged copies of this gene. This makes it more
likely that you will develop serious lung or liver problems.
Although it's helpful to know whether you have this genetic disorder, a positive test
result may affect your emotional health and your health insurance. For this reason,
some groups, including the nonprofit Alpha-1 Foundation, recommend talking with a
genetic counselor before getting a medical test that will remain in your health records.
Contact a health professional who specializes in advising patients about genetic diseases.
Why do I need this test?
The only way to find out whether you have this genetic disorder is to get tested.
Your doctor may order this test if you have these problems:
Asthma that can't be controlled through aggressive treatment
Shortness of breath during mild exercise
Rapid heartbeat when you stand up
Bumpy or itchy skin
Chronic obstructive pulmonary disease, or COPD
Emphysema, a serious, progressive lung disease that causes breathing difficulties
Bronchiectasis, a lung problem that causes chronic dilation of the airways
Blood in your vomit
Swelling in your abdomen or legs
Unexplained liver problems, especially if they appear in childhood
Unintentional weight loss
Infants who have yellow skin, a sign of jaundice, may also be tested.
Your health care provider may also recommend the test if someone in your family has
a history of the above conditions.
What other tests might I have along with this test?
Your health care provider may recommend other tests to rule out other conditions:
Pulmonary function testing. A series of tests to see how well your lungs work.
Chest radiography. X-ray of your lungs.
HRCT (high-resolution CT) and densitometry. More detailed X-rays of your lungs and tests to measure any lung and liver damage.
Liver function tests. A series of blood tests to see how well your liver works.
Abdominal ultrasound. A test that uses sound waves to find evidence of liver damage.
Liver biopsy. A procedure that involves taking a tiny sample of your liver to look for disease.
Your provider may do a series of tests on the serum in your blood to find the damaged
genes. These tests include:
Serum AAT concentrations. Tests on a blood sample to look for the AAT protein.
Serum protein electrophoresis with thin-layer isoelectric focusing, which is considered a more accurate test for
Genetic test. You may consider getting a genetic test before getting a blood test. The genetic
test can be done with a blood sample or a swab from inside your mouth.
What do my test results mean?
Many things may affect your lab test results, including the method each lab uses to
do the test. Even if your test results are different from the normal value, you may
not have a problem. To learn what the results mean for you, talk with your health
A normal result will be above 50 to 80 milligrams per deciliter (mg/dL), depending
on how the results were done. If your levels are too low, it may be a sign that you
have one damaged gene, which means you are a carrier, or two damaged genes, which
means you have AAT deficiency. Talk with your health care provider about what your
test results mean.
How is this test done?
The test requires a blood sample, which is drawn through a needle from a vein in your
Does this test pose any risks?
Taking a blood sample with a needle carries risks that include bleeding, infection,
bruising, and feeling dizzy. When the needle pricks your arm, you may feel a slight
pain or sting. Afterward, the site may be sore.
Although the physical risks of the test are slight, it may be emotionally upsetting
to find out you have a genetic risk for certain diseases. Because it may reveal a
chronic health condition, the test may also affect your coverage for health and life
insurance. For these reasons, experts recommend seeking genetic counseling.
What might affect my test results?
If the test is done properly, the results should be accurate. But always keep in mind
the possibility of a falsely abnormal result.
How do I get ready for this test?
You don't have to prepare for this test.