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Alpha-1 Antitrypsin (Serum) Concentration

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

This 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 can help diagnose or monitor conditions affecting the lungs or liver."]

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

Key facts at a glance

LOINC
42440-8
Short code
Deprecated Neck XR Lat
Synonyms
Deprecated Neck XR Lat
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
22
Ref high
198
Critical range
— – 10000 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
xr
CPT
82553
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 Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like chronic cough, shortness of breath, or liver-related issues such as jaundice, fatigue, or abdominal pain. It may also be used to assess risk for lung diseases like emphysema or chronic obstructive pulmonary disease (COPD) or liver diseases like cirrhosis.

What to Expect Before the Test

No special preparation is typically needed. You may be asked to fast for 8–12 hours before the test if it involves drawing blood from a vein. Bring any medications you’re currently taking to your appointment.

How the Test Is Performed

A healthcare professional will insert a needle into a vein in your arm to draw a small amount of blood. The blood sample is then sent to a lab for analysis of Alpha-1 Antitrypsin protein levels.

What the Results Mean

Results are compared to a reference range, which varies by lab. Low levels may indicate genetic disorders (like Alpha-1 Antitrypsin Deficiency) or liver disease, while high levels may be normal or associated with certain conditions like cirrhosis.

Reference range

Adult males: 22-198 U/L; Females: 22-198 U/LN/A

Specimen: serum

No special preparation required. Inform provider of any chest pain or symptoms.

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 low Alpha-1 Antitrypsin levels?
Low levels are most commonly due to a genetic mutation passed down through families. However, other conditions like liver disease, certain infections, or medications may temporarily lower levels. If you have a family history of lung or liver disease, this test may be particularly important.
How often should I get this test?
If you have Alpha-1 Antitrypsin Deficiency, your doctor may recommend regular monitoring to track lung or liver health. For others, this test may be ordered occasionally if symptoms suggest a possible deficiency or related condition. Follow your healthcare provider’s guidance.
Can lifestyle changes affect Alpha-1 Antitrypsin levels?
While lifestyle factors like smoking, air pollution, or chronic infections can worsen lung or liver damage, they do not directly alter Alpha-1 Antitrypsin protein levels. However, avoiding smoking and managing health conditions can help prevent complications linked to low A1AT levels.
  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