Alpha-1 antitrypsin deficiency test

A blood test can measure the amount of alpha-1 antitrypsin (AAT) in your blood. You may have AAT deficiency if your levels are low or if the blood test is not able to find any AAT in your blood. If your AAT level is lower than normal, the blood sample can be tested to look for abnormal types of alpha-1 antitrypsin. People who carry the changed gene may be more at risk for symptoms if they have certain types of alpha-1 antitrypsin.

Normal alpha-1 antitrypsin levels are 100–200 mg/dL or 1.0–2.0 g/L.

Although this blood test is highly reliable, no test is 100% accurate. This test cannot predict when—or whether—you will develop symptoms or how severe they will be.

An AAT deficiency test measures the level of AAT in the blood. The Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2017 clinical guidelines recommend a one-time testing for all people with COPD. And the American Thoracic Society and the European Respiratory Society recommend testing for an AAT deficiency for people who have:

• Symptoms of COPD and have been diagnosed with emphysema or COPD.
• Asthma with airflow blockage that is not completely resolved after treatment with medicine that opens the lung airways (bronchodilators).
• Unexplained liver disease.
• No symptoms, but lung tests show obstruction, and risk factors such as smoking are present.
• Necrotizing panniculitis.
• A brother or sister who is AAT-deficient.

Screening for an AAT deficiency in the general public is not currently recommended.