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Alpha-1 Antitrypsin (A1AT) Serum Level

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

This blood test measures the level 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.

Quick summary

["A1AT levels help assess lung and liver health, especially in conditions like chronic obstructive pulmonary disease (COPD) or genetic disorders."]

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

Key facts at a glance

LOINC
38029-5
Short code
Deprecated US Chest Bx needle guide
Synonyms
Deprecated US Chest Bx needle guide
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
us
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 Is Done

Your healthcare provider may order an A1AT test if you have symptoms like persistent cough, shortness of breath, or liver issues. It’s also used to diagnose or monitor conditions like Alpha-1 Antitrypsin Deficiency, a genetic disorder that can affect the lungs and liver over time.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the test if it involves drawing blood from a vein. Wear a loose shirt for easy access.

How the Test Is Performed

A healthcare professional will insert a needle into a vein in your arm. You may feel a brief pinch, but the procedure is quick. Blood is collected into a tube and sent to the lab for analysis.

What the Results Mean

Results are compared to a reference range, but exact values can vary by lab. Low levels may indicate Alpha-1 Antitrypsin Deficiency, while high levels could suggest liver disease or other conditions. Your provider will discuss findings with you.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Alpha-1 Antitrypsin (A1AT)

Frequently asked questions

What does a low A1AT level mean?
A low A1AT level is often linked to Alpha-1 Antitrypsin Deficiency, a genetic condition that can lead to lung diseases (like emphysema) or liver problems. Early diagnosis helps manage symptoms and prevent complications.
How does A1AT relate to lung health?
A1AT protects lung tissue from enzymes that cause inflammation and damage. Low levels may increase your risk of chronic lung diseases, especially if you smoke or have a family history of the condition.
Can diet or supplements affect A1AT levels?
Dietary changes alone won’t change A1AT levels, but certain medications (like some antibiotics or liver disease treatments) may influence them. Always ask your provider about potential interactions.
  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