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Alpha-1 Antitrypsin, Serum/Plasma — Substance Concentration

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

Measures the concentration of alpha-1 antitrypsin, a liver-made protein that protects the lungs from inflammation.

Quick summary

["This blood test helps evaluate alpha-1 antitrypsin levels, which may be relevant to liver or lung disease."]

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

Key facts at a glance

LOINC
79590-6
Short code
A-AIB SerPl-sCnc
Synonyms
A-AIB SerPl-sCnc
Category
liver
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

What is this test?

This test measures the amount of alpha-1 antitrypsin, a protein made by the liver. The protein circulates in the blood and helps protect lung tissue from inflammatory damage.

Why might I need this test?

A clinician may order this test when there is concern about alpha-1 antitrypsin deficiency, unexplained liver disease, or certain chronic lung conditions. It may also be used to follow a previously identified low or abnormal alpha-1 antitrypsin level.

How is the test performed?

A blood sample is drawn from a vein. The laboratory separates serum or plasma and measures the alpha-1 antitrypsin concentration using an approved laboratory method.

How do I prepare for the test?

No special preparation is usually required. Illness, inflammation, pregnancy, and liver disease can affect the result, so tell your clinician about current symptoms, medical conditions, and medicines. Do not stop prescribed medicines unless your clinician instructs you to do so.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

A low alpha-1 antitrypsin level may indicate a deficiency, which can increase the risk of emphysema and certain forms of liver disease. An elevated level may occur with inflammation, infection, pregnancy, or liver disease and does not always indicate a genetic deficiency. Results should be interpreted by a clinician, often alongside liver tests and an inflammation marker such as C-reactive protein.

Short name

Alpha-1 Antitrypsin (A1AT)

Frequently asked questions

Does this test diagnose emphysema?
No. The test measures alpha-1 antitrypsin and can help evaluate whether a deficiency may be contributing to lung or liver disease, but it is not a stand-alone diagnosis of emphysema.
What if my result is above the expected range?
An elevated result can occur during inflammation or with certain liver conditions. Your clinician will interpret it in the context of your symptoms, other laboratory results, and medical history.
Is genetic testing needed?
Sometimes. An unexpectedly low or borderline alpha-1 antitrypsin level may prompt confirmatory testing or evaluation for alpha-1 antitrypsin deficiency, including additional laboratory or genetic tests.
  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