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Alpha-1 Antitrypsin (A1AT) Serum Level

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

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.

Quick summary

["A1AT helps protect your lungs and liver; low levels may indicate genetic risk for lung disease or liver problems."]

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

Key facts at a glance

LOINC
37916-4
Short code
Deprecated US LN Bx needle guide
Synonyms
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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 this test if you have symptoms like chronic cough, shortness of breath, or liver issues. It’s also used to screen for genetic conditions affecting A1AT levels, especially in families with a history of lung or liver diseases.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample, usually drawn from your arm. The test is quick and typically done in a lab setting.

What the Results Mean

Results help determine if your A1AT levels are within normal range or if they’re too low. Low levels may suggest a genetic disorder linked to lung or liver disease.

Common Conditions Monitored

Low A1AT levels are often associated with conditions like Alpha-1 Antitrypsin Deficiency, which can lead to chronic obstructive pulmonary disease (COPD) or cirrhosis.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

A1AT

Frequently asked questions

What causes low Alpha-1 Antitrypsin levels?
Low A1AT levels are most commonly due to a genetic mutation passed down through families. Other rare causes may include certain liver diseases or conditions that affect protein production.
How often should I get this test?
If you have a family history of Alpha-1 Antitrypsin Deficiency, your doctor may recommend regular testing. Otherwise, this test is usually done only when symptoms or risk factors suggest it’s needed.
Can diet or lifestyle changes affect A1AT levels?
Diet and lifestyle factors like smoking or heavy alcohol use can worsen lung or liver damage, but they don’t directly change A1AT levels. Focus on managing symptoms and following your doctor’s advice for long-term care.
  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