Alpha-1 Antitrypsin (A1AT) Serum Concentration
This test measures the level of Alpha-1 Antitrypsin, a protein produced by the liver that helps protect the lungs from damage caused by enzymes released during inflammation.
["A1AT helps prevent lung disease and supports immune function; low levels may indicate genetic risk or liver issues."]
Key facts at a glance
- LOINC
- 13142-5
- Short code
- Deprecated S pneum3 Ab sp2 Ser-aCnc
- Synonyms
- Deprecated S pneum3 Ab sp2 Ser-aCnc
- Category
- coagulation
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why This Test Matters
Alpha-1 Antitrypsin is crucial for maintaining lung health by inhibiting enzymes that can break down lung tissue. Deficiencies in this protein can lead to chronic lung diseases, such as emphysema, even in the absence of smoking history. This test is often used to screen for genetic conditions that may predispose individuals to lung or liver problems.
What to Expect Before the Test
No special preparation is typically required, but you may be asked to fast for 8–12 hours before the test if your blood is drawn early in the morning. Wear comfortable clothing and plan to stay near the testing site for a short time, as blood draws usually take only a few minutes.
What Happens During the Test
A healthcare provider will insert a small needle into a vein in your arm. A small amount of blood will be drawn into a test tube. This is usually painless and may cause a slight sting. The process takes less than five minutes.
What the Results Mean
Results are compared to a reference range that reflects typical levels in healthy individuals. Low levels of Alpha-1 Antitrypsin may indicate a genetic disorder (such as Alpha-1 Antitrypsin Deficiency) or liver disease. High levels may be due to liver conditions or certain medications. Your healthcare provider will discuss your results in the context of your overall health.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
A1AT Serum
Frequently asked questions
Alpha-1 Antitrypsin Deficiency is a genetic condition that can cause lung diseases (like emphysema) and liver disorders. Early screening is important for individuals with a family history of the condition or symptoms like persistent coughing, shortness of breath, or unexplained liver issues. Treatment focuses on managing symptoms and, in some cases, enzyme replacement therapy.
A low level may suggest a genetic predisposition to lung or liver disease. If you have a family history of Alpha-1 Antitrypsin Deficiency or related conditions, your doctor may recommend further testing or monitoring. If you have symptoms like chronic coughing or breathing difficulties, this test could help identify underlying causes.
While diet and lifestyle factors like smoking can influence lung health, they do not directly alter Alpha-1 Antitrypsin levels. However, smoking accelerates lung damage in individuals with low A1AT levels, so quitting is strongly recommended.
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy