Serum or Plasma Alpha-1 Antitrypsin (A1AT) Concentration
This test measures the amount of Alpha-1 Antitrypsin, a protein produced by the liver that helps protect the lungs and other organs from damage caused by enzymes released during inflammation.
["Alpha-1 Antitrypsin helps prevent lung disease and liver problems; low levels may signal genetic risk or chronic conditions."]
Key facts at a glance
- LOINC
- 103120-2
- Short code
- Hazelnut (rCor a) 14 IgE RAST
- Synonyms
- Hazelnut (rCor a) 14 IgE RAST
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 10
- Ref high
- 40
- Critical range
- — – 500 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- rast
- CPT
- 84484
- SNOMED
- 302774002
- 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 plays a critical role in maintaining lung and liver health by inhibiting enzymes that can cause tissue damage. Low levels of this protein are linked to conditions like emphysema (a type of chronic obstructive pulmonary disease) and liver diseases such as cirrhosis. Your doctor may order this test if you have a family history of lung or liver disease, symptoms like persistent coughing, shortness of breath, or unexplained fatigue.
What to Expect Before the Test
No special preparation is needed for this test. You may have a blood sample drawn from a vein in your arm, or if testing plasma, it might be collected during a routine blood draw. If you’re taking blood, you might feel a slight pinch, but it usually doesn’t cause significant discomfort. If you’re concerned about needles, let your healthcare provider know.
What the Results Mean
Results are used to assess whether your Alpha-1 Antitrypsin levels are within the normal range or if they’re lower than expected. Low levels may indicate a genetic condition called Alpha-1 Antitrypsin Deficiency (A1ATD), which can increase your risk for lung or liver disease. Your doctor will discuss the results in the context of your medical history and symptoms.
Common Causes and Conditions
Low Alpha-1 Antitrypsin levels can be due to genetic mutations (A1ATD), chronic liver disease, or certain medications. If your levels are low, your doctor may recommend further testing or lifestyle changes to manage symptoms and reduce risk. High levels may occur in some inflammatory conditions or during pregnancy.
Reference range
Adult: 10-40 U/LN/A
No special preparation required. Avoid fatty meals before the test if possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Alpha-1 Antitrypsin Level
Frequently asked questions
What Might Trigger This Test?
How Often Should I Get This Test?
Can I Avoid This Test?
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 17, 2026. · Read our editorial policy