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Alpha-1 Antitrypsin (A1AT) in Serum/Plasma

Published: August 9, 2026Updated: August 16, 2026

This test measures the level of Alpha-1 Antitrypsin, a protein produced mainly in the liver that helps protect the lungs and other organs from damage caused by enzymes released during inflammation.

Quick summary

["A1AT levels help assess risk for lung diseases like emphysema and liver disorders."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
21084-9
Short code
A flavus Ab CSF Ql ID
Synonyms
A flavus Ab CSF Ql ID
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
immune-diffusion
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms of lung disease (such as shortness of breath, chronic cough), a family history of Alpha-1 Antitrypsin deficiency, or if you have liver problems. It may also be used to monitor disease progression or response to treatment in certain conditions.

What to Expect Before the Test

No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if it involves drawing blood from a vein. If you’re having a urine test, follow any specific instructions your provider gives you.

How the Test Works

Blood is drawn from a vein in your arm and sent to a lab. The lab uses a specialized method (likely immunoassay or electrophoresis) to measure the amount of Alpha-1 Antitrypsin protein in your serum or plasma.

Possible Results and Next Steps

Results are compared to a reference range, which varies by lab. Low levels may indicate Alpha-1 Antitrypsin deficiency, while high levels could be due to liver disease or other conditions. Your provider will discuss results with you and recommend next steps, such as further testing or treatment options.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

A1AT Serum/Plasma

Frequently asked questions

What causes low Alpha-1 Antitrypsin levels?
Genetic mutations (inherited deficiency) are the most common cause. Other factors, such as liver disease, infections, or certain medications, may temporarily lower levels, but genetic testing is needed to confirm deficiency.
Can diet or supplements affect A1AT levels?
Dietary changes alone won’t change A1AT levels, but some supplements (like vitamin E or antioxidants) may interact with lab tests. Always check with your provider before taking new supplements.
Is this test painful?
The blood draw may cause mild discomfort or bruising at the site, but most people tolerate it well. If you’re nervous, let your provider know—they can offer tips or use a smaller needle if needed.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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