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Alpha-1 Antitrypsin (A1AT) in Serum or Plasma

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.

Quick summary

["Alpha-1 Antitrypsin levels help identify potential lung or liver conditions linked to genetic mutations."]

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

Key facts at a glance

LOINC
22565-6
Short code
Deprecated S pneumB Ab Ser Ql
Synonyms
Deprecated S pneumB Ab Ser Ql
Category
coagulation
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 if you have symptoms like chronic cough, shortness of breath, or liver problems, or if you have a family history of Alpha-1 Antitrypsin deficiency. It can also be used to monitor lung or liver function in certain conditions.

What to Expect Before the Test

No special preparation is usually needed. You may be asked to fast before the test if it involves drawing blood, but this depends on your specific situation. Bring any medications you’re taking to your appointment.

What Happens During the Test?

A healthcare professional will draw blood from a vein in your arm. You may feel a small pinch, but it usually doesn’t cause discomfort afterward. The blood sample is then sent to a lab for analysis.

What Are Possible Results?

Results are compared to standard reference ranges to determine if your Alpha-1 Antitrypsin levels are within normal limits or if they suggest a deficiency or other conditions. Your doctor will discuss these results with you.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Alpha-1 Antitrypsin Level

Frequently asked questions

What does a low Alpha-1 Antitrypsin level mean?
A low level may suggest Alpha-1 Antitrypsin deficiency, which can lead to lung or liver issues over time. Your doctor will guide you on next steps, which may include genetic testing or monitoring.
How is this test different from other protein tests?
This test specifically measures Alpha-1 Antitrypsin, a distinct protein involved in lung and liver protection. Other protein tests may measure different types of proteins, such as albumin or globulins, for various health assessments.
Can diet affect Alpha-1 Antitrypsin levels?
Diet generally does not directly affect Alpha-1 Antitrypsin levels, as these are primarily produced by the liver. However, maintaining a balanced diet can support overall liver health, which may indirectly benefit your test 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