How Is Alpha-1 Antitrypsin Deficiency Diagnosed?

Alpha-1 antitrypsin (AAT) deficiency is usually diagnosed after you develop a lung or liver disease that's linked to AAT deficiency.

Because of this, a number of different health care professionals may be involved in the diagnosis of AAT deficiency. These include primary care doctors, pulmonologists (lung specialists), and hepatologists (liver specialists).

To check whether the disease you have may be related to AAT deficiency, your doctor will:

• Ask about possible risk factors. A common sign of AAT deficiency is when you have a lung or liver disease without any obvious causes or risk factors. Another is if you have emphysema at an unusually early age (45 years or younger).
• Ask about your family's medical history. If you have close family members who have AAT deficiency, you're more likely to have the condition.

Diagnostic Tests

If your doctor thinks that you have AAT deficiency, he or she may order tests to check for the condition. He or she also may order tests to check for lung- or liver-related conditions.

A genetic test is the most certain way to check for AAT deficiency. This test will show whether you have altered AAT genes.

A blood test also may be used. This test checks the levels of AAT protein in your blood. If the AAT levels are a lot lower than normal, it's likely that you have AAT deficiency.

Lung-Related Tests

If you have a lung disease related to AAT deficiency, your doctor may recommend pulmonary function tests and high-resolution computed tomography (CT) scanning.

Pulmonary function tests show how well you're able to blow air out of your lungs. They also show how much air gets into your lungs when you breathe. These tests are used to check how severe your lung disease is and how well treatment is working.

High-resolution CT scanning uses x rays to create detailed pictures of sections of the body. CT scans show whether you have emphysema and how severe it is.