What is an alpha-1 antitrypsin (AAT) test?
This test measures the amount of alpha-1 antitrypsin (AAT) in the blood. AAT is a protein that is made in the liver. It helps protect your lungs from damage and diseases, such as emphysema and chronic obstructive pulmonary disease (COPD).
AAT is made by certain genes in your body. Genes are the basic units of heredity passed down from your parents. They carry information that determines your unique traits, such as height and eye color. Everyone inherits two copies of the gene that makes AAT, one from their father and one from their mother. If there is a mutation (change) in one or both copies of this gene, your body will make less AAT or AAT that doesn't work as well as it should.
If you have two mutated copies of the gene, it means you have a condition called AAT deficiency. People with this disorder have a higher risk of getting lung disease or liver damage before the age of 45.
If you have one mutated AAT gene, you may have lower than normal amounts of AAT, but mild or no symptoms of disease. People with one mutated gene are carriers of AAT deficiency. This means you don't have the condition, but you could pass the mutated gene on to your children.
An AAT test can help show if you have the genetic mutation that puts you at risk for disease.
Other names: A1AT, AAT, alpha-1-antiprotease deficiency, α1-antitrypsin
