Short answer
Alpha-1 antitrypsin deficiency is an inherited condition that can raise risk for lung disease and liver disease. Testing may include an alpha-1 antitrypsin blood level, protease inhibitor typing, and SERPINA1 genetic testing. A direct-to-consumer DNA result should not be treated as a complete clinical workup.
Test types
| Test | What it adds | Limit |
|---|---|---|
| AAT blood level | Shows whether the protein level is low. | Inflammation can affect levels, and level alone may not explain genotype. |
| PI typing | Identifies common deficient protein variants. | May need genetic confirmation in some cases. |
| SERPINA1 genetic test | Looks for variants that cause alpha-1 antitrypsin deficiency. | Panel content varies; rare variants may require specialized testing. |
| Family testing | Helps relatives understand inherited risk. | Needs careful explanation of carrier and disease-risk patterns. |
When it comes up
Testing may be discussed with early COPD or emphysema, emphysema without typical smoking history, unexplained liver disease, family history of alpha-1 antitrypsin deficiency, or certain abnormal protein patterns.
Why the level and genetics are read together
The AAT blood level can be a clue, but it is not the whole answer. NHLBI and MedlinePlus both note that inherited alpha-1 antitrypsin deficiency can affect lung and liver risk, and that testing often combines a protein level with genotype or phenotype confirmation so the result is not overread or underread.
Questions to ask
- Was this a protein-level test, phenotype test, genetic test, or a combination?
- Do lung symptoms, liver tests, smoking history, and family history fit the result?
- Should relatives be offered testing or genetic counseling?
- Does the result change smoking avoidance, occupational exposure choices, liver monitoring, or specialist follow-up?
What follow-up may include
Follow-up may include repeating the AAT level when inflammation is not distorting the result, PI typing or SERPINA1 genetic testing, liver tests, pulmonary evaluation, and family testing or genetic counseling when a pathogenic variant is confirmed.
Related guides: direct-to-consumer genetic testing, when to use a genetic counselor, liver function tests, and whole genome sequencing reports.
FAQ
What does alpha-1 testing look for?
It often combines an AAT blood level with phenotype or SERPINA1 genetic testing to see whether low protein levels reflect inherited alpha-1 antitrypsin deficiency.
Why do the blood level and genetics need to be read together?
The blood level can be influenced by inflammation, while genotype or phenotype helps show whether the low level is really due to SERPINA1-related deficiency.
What is PI typing?
PI typing checks the protein pattern, which can help identify common deficient alpha-1 antitrypsin variants and confirm the diagnosis in some cases.
When is family testing useful?
Family testing is useful when a pathogenic variant is confirmed, because relatives may have inherited lung or liver risk even if they feel well.
Can a low AAT level happen for other reasons?
Yes. Inflammation and other clinical factors can affect the measured level, so the result is interpreted with symptoms, liver tests, and the genetic or phenotype result.
Does a negative result rule out alpha-1 deficiency?
Not always. The answer depends on which test was done and whether the panel covered the relevant variants, so the specimen type and method matter.