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Serum or plasma concentration of alpha-1 antitrypsin (A1AT) measured by immunoassay

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

This test measures the amount of alpha-1 antitrypsin, a protein produced by the liver that helps protect the lungs from damage caused by enzymes released during inflammation or injury.

Quick summary

["Alpha-1 antitrypsin helps prevent lung disease and supports immune function."]

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

Key facts at a glance

LOINC
24920-1
Short code
XR Skull Lat
Synonyms
XR Skull Lat
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
xr
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 of lung disease (like chronic bronchitis or emphysema), a family history of alpha-1 antitrypsin deficiency, or other conditions linked to low levels of this protein. It may also be checked during routine evaluations for certain genetic or inflammatory conditions.

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 on blood thinners, let your provider know before the test.

What the Results Mean

Low levels of alpha-1 antitrypsin can increase your risk of lung diseases or liver problems. High levels may indicate certain liver conditions or other health concerns. Your results will be reviewed by a healthcare provider to guide next steps.

Common Conditions Linked to Results

Low alpha-1 antitrypsin levels are most strongly associated with **alpha-1 antitrypsin deficiency**, a genetic condition that can lead to chronic lung diseases like emphysema or liver disease. Other conditions, such as chronic obstructive pulmonary disease (COPD) or certain inflammatory conditions, may also be monitored with this test.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Alpha-1 Antitrypsin Level

Frequently asked questions

What causes abnormal alpha-1 antitrypsin levels?
Abnormal levels can result from genetic mutations (deficiency), liver disease, chronic lung conditions, or certain medications. If you have a family history of lung or liver disease, your provider may check this test to assess risk.
Can diet or lifestyle affect this test?
Dietary changes alone won’t alter alpha-1 antitrypsin levels, but smoking increases lung damage and may worsen symptoms in people with deficiency. Avoiding smoking and maintaining a healthy lifestyle can support overall lung health.
How often should this test be repeated?
If you have alpha-1 antitrypsin deficiency, your provider may recommend follow-up tests every few years or more often if symptoms change. Regular monitoring helps track disease progression and adjust treatment as 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