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Alpha-1 Antitrypsin (A1AT) Serum Concentration

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

This test measures the level 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

["A1AT helps prevent lung disease and supports immune function; low levels may indicate genetic risk or liver disease."]

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

Key facts at a glance

LOINC
101908-2
Short code
AP3B2 Ab Titr Spec
Synonyms
AP3B2 Ab Titr Spec
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 This Test Is Done

Your doctor may order this test if you have symptoms like chronic cough, wheezing, or lung problems, or if you have a family history of conditions like Alpha-1 Antitrypsin Deficiency (AATD). It’s also used to monitor liver health or check for genetic risks.

What to Expect Before the Test

No special preparation is needed, but you may fast for 8–12 hours before the draw if instructed. Bring your questions or any medications you’re taking.

How the Test Works

A blood sample is taken from a vein in your arm. The sample is sent to a lab where it’s analyzed using an immunoassay method to measure your A1AT protein concentration.

Possible Results & Next Steps

Results are compared to a reference range, but exact values aren’t provided here. Low levels may prompt further testing or genetic counseling; high levels may need liver monitoring.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

A1AT Serum

Frequently asked questions

What causes abnormal A1AT levels?
Abnormal results may stem from genetic mutations (e.g., AATD), liver disease, chronic inflammation, or smoking. Conditions like cirrhosis or lung diseases can also affect levels.
How long does it take to get results?
Results typically arrive within 1–3 business days, depending on your lab. Follow-up may include additional tests or doctor visits if needed.
Can diet or exercise affect A1AT levels?
Dietary changes or exercise alone rarely alter A1AT levels. However, smoking can lower A1AT and worsen lung disease risk; quitting may help stabilize levels over time.
  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