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Serum or Plasma Alpha-1 Antitrypsin (A1AT) Concentration

Published: August 9, 2026Updated: August 16, 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

["Alpha-1 Antitrypsin helps prevent lung damage and can be checked if you have symptoms of lung disease or a family history of genetic disorders affecting this protein."]

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

Key facts at a glance

LOINC
42436-6
Short code
XR ST Lat+Towne
Synonyms
XR ST Lat+Towne
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 Is This Test Done?

Your healthcare provider may order this test to diagnose or monitor conditions like chronic obstructive pulmonary disease (COPD), emphysema, or alpha-1 antitrypsin deficiency—a genetic disorder that can lead to lung and liver problems. It’s also used in screening for inherited lung diseases in high-risk individuals.

What Does a Low or High Level Mean?

Low levels of Alpha-1 Antitrypsin may indicate a genetic deficiency, which can increase your risk of lung diseases. High levels might be seen in certain liver diseases or during pregnancy, but further evaluation is needed to understand the cause.

Sample Collection and Preparation

Blood is drawn from a vein in your arm. The sample is collected in a tube and sent to the lab for analysis. If you’re taking medications or have recent infections, your provider may advise timing your test to avoid potential effects on results.

Common Conditions Monitored

This test is critical for diagnosing alpha-1 antitrypsin deficiency, which can cause lung diseases like emphysema or liver cirrhosis. It’s also used to assess lung function in patients with chronic lung conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Alpha-1 Antitrypsin plays a protective role in the lungs and liver. Low levels are linked to progressive lung damage, particularly in smokers or those with genetic predispositions. Regular monitoring helps manage symptoms and prevent complications.

Short name

Alpha-1 Antitrypsin

Frequently asked questions

What causes abnormal Alpha-1 Antitrypsin levels?
Abnormal levels can result from genetic mutations (e.g., alpha-1 antitrypsin deficiency), liver diseases, chronic lung conditions, or certain medications. If your provider suspects an underlying cause, they may recommend additional tests.
How often should I get this test?
Your provider will determine the frequency based on your health status. For those with a known deficiency, testing may be done annually or more often to monitor progression. Follow-up depends on your symptoms and treatment plan.
Can diet or lifestyle affect this test?
Smoking, alcohol consumption, and certain medications (like oral contraceptives) can influence Alpha-1 Antitrypsin levels. Avoid smoking and limit alcohol before testing if advised by your provider to get the most accurate results.
  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