Alpha-1 antitrypsin (AAT) deficiency usually is diagnosed after you develop a lung or liver disease that's related to the condition.
Your doctor may suspect AAT deficiency if you have signs or symptoms of a serious lung condition, especially emphysema, without any obvious cause. He or she also may suspect AAT deficiency if you develop emphysema when you're 45 years old or younger.
Many doctors may be involved in the diagnosis of AAT deficiency. These include primary care doctors, pulmonologists (lung specialists), and hepatologists (liver specialists).
To diagnose AAT deficiency, your doctor will:
- Ask about possible risk factors. Risk factors include smoking and exposure to dust, fumes, and other toxic substances.
- Ask about your medical history. A common sign of AAT deficiency is if you have a lung or liver disease without any obvious causes or risk factors. Another sign is if you have emphysema at an unusually early age (45 years or younger).
- Ask about your family's medical history. If you have bloodline relatives who have AAT deficiency, you're more likely to have the condition.
Your doctor may recommend tests to confirm a diagnosis of AAT deficiency. He or she also may recommend 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 faulty AAT genes.
A blood test also may be used. This test checks the level of AAT protein in your blood. If the level is a lot lower than normal, it's likely that you have AAT deficiency.
Lung function tests measure how much air you can breathe in and out, how fast you can breathe air out, and how well your lungs deliver oxygen to your blood. These tests may show how severe your lung disease is and how well treatment is working.
High-resolution CT scanning uses x rays to create detailed pictures of parts of the body. A CT scan can show whether you have emphysema or another lung disease and how severe it is.