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Alpha-1 Antitrypsin (A1AT) Serum Concentration by Immunoassay

Published: August 9, 2026Updated: August 17, 2026

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

Quick summary

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

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
14558-1
Short code
M tb DNA Gast Ql NAA+probe
Synonyms
M tb DNA Gast Ql NAA+probe
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
probe-amp-tar
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 (A1AT) is crucial for maintaining lung tissue integrity. Low levels can increase your risk of lung diseases, such as emphysema, or liver problems like cirrhosis. This test helps doctors monitor your condition and guide treatment decisions.

What to Expect Before the Test

No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw a blood sample. If you’re nervous, let your healthcare provider know—they can help make it more comfortable.

What the Results Mean

Results show your current A1AT level in the blood. While reference ranges vary by lab, doctors interpret results based on your medical history and symptoms. Very low levels may signal genetic mutations linked to lung or liver disease.

Common Conditions Monitored

Doctors use A1AT testing to diagnose or monitor conditions like alpha-1 antitrypsin deficiency (AATD), a genetic disorder that can lead to lung diseases (e.g., emphysema) or liver disease (e.g., cirrhosis). It’s also checked in people with unexplained lung or liver issues.

Reference range

Adult: 10-40 U/LN/A

Specimen: serum

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 (A1AT)

Frequently asked questions

What causes abnormal A1AT levels?
Abnormal A1AT levels can result from genetic mutations (e.g., alpha-1 antitrypsin deficiency), chronic liver disease, or certain medications. If your results are low, your doctor may check for hereditary factors or other health conditions affecting your liver or lungs.
How often should I get this test?
Your doctor will determine how often you need this test based on your medical history, symptoms, and risk factors. For example, people with alpha-1 antitrypsin deficiency may need regular monitoring, while others may only need it if symptoms arise.
Can diet or lifestyle changes affect A1AT levels?
While diet and lifestyle (e.g., smoking, alcohol) can influence overall health, they don’t directly alter A1AT levels. However, smoking is linked to lung damage and may worsen symptoms in people with AATD. Always follow your doctor’s advice for managing related conditions.
  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 17, 2026. · Read our editorial policy