Alpha-1 Antitrypsin Testing
Reviewed
This test measures the amount of alpha-1 antitrypsin (AAT) protein in your blood or looks for gene changes that cause AAT deficiency. AAT deficiency is a genetic condition that can lead to lung disease (such as COPD) and liver disease (such as cirrhosis). Testing can help diagnose the condition in people with symptoms, screen those with a family history, or guide treatment for lung disease.
Preparation and collection
You don't need any special preparations for an AAT test.
Understanding this test
Use the reference interval and units printed by the laboratory that performed the test. A result outside that interval is not a diagnosis by itself, and a result inside it does not rule out every condition. Your symptoms, history, medicines, timing, and related tests can change what the result means.
- A low AAT blood level alone is not diagnostic; a genotype or phenotype test is needed to confirm AAT deficiency.
- A normal AAT level does not completely rule out all forms of AAT deficiency, especially if symptoms are present.
- Genetic testing can identify carriers (people with one mutated copy of the gene) who are at slightly higher risk of developing lung disease, especially if they have other risk factors such as smoking.
- There is no cure for AAT deficiency, but treatments can help prevent the condition from getting worse.
What to do next
If you have questions about your results, talk to your provider. If you are thinking about having AAT testing or have received abnormal results, it may be helpful to speak with a genetic counselor. A genetic counselor can help you understand the risks and benefits of testing for you and your family, and after testing, can help you understand your results and provide information on the condition, including your risk of passing it to your children.
Evidence source
U.S. National Library of Medicine: Alpha-1 Antitrypsin Testing