There are two types of testing currently used to diagnose Alpha-1 antitrypsin deficiency: DNA testing and protein testing – also called phenotyping. Protein testing has been around for many years and is considered the gold standard for diagnosing Alpha-1. DNA testing is a more recent development.

Protein testing is useful in diagnosing Alpha-1 because it looks at the total amount of AAT circulating in the blood. It can identify people with Alpha-1 who may have a less common gene change for which testing is not currently available. However, protein testing does not identify the underlying cause of Alpha-1.

Genetic testing looks for the two most common gene changes associated with Alpha-1 ­– known as S and Z. A genetic test can also confirm a diagnosis, and it is the most accurate way to make family planning decisions and help relatives learn about their own risk.

Many people who have been diagnosed by protein testing have not had DNA testing. DNA testing is valuable because it can identify the underlying genetic cause of Alpha-1 – with this information, other at-risk family members can be tested to determine if they have Alpha-1 or are carriers.

If you have signs or symptoms of Alpha-1, genetic testing can tell you whether you have one or more of the two most common genetic changes related to Alpha-1 antitrypsin deficiency. (These are called the S and Z forms of the AAT gene.)

Knowing which gene mutations you have can help you begin appropriate screening, make informed treatment decisions, modify lifestyle or occupational exposures, identify at-risk family members, and make informed family planning decisions.