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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

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

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

Key facts at a glance

LOINC
16415-2
Short code
A flavus Ab CSF Ql
Synonyms
A flavus Ab CSF Ql
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may order this test if you have symptoms like chronic cough, shortness of breath, or if you have a family history of conditions like alpha-1 antitrypsin deficiency, which can lead to lung diseases like emphysema or liver problems.

What to Expect Before the Test

No special preparation is needed. You may have a blood sample drawn from a vein in your arm, or in some cases, a urine sample may be collected if testing for certain conditions. Always follow your provider’s instructions.

How the Test Works

Blood or plasma is collected and analyzed using an immunoassay method to measure the concentration of Alpha-1 Antitrypsin protein. This helps determine if levels are within a typical range or if they are lower than expected.

What the Results Mean

Results are compared to a reference range to identify if your levels are normal or if they are below normal. Low levels may suggest genetic disorders, liver disease, or other health conditions that need further evaluation.

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 low Alpha-1 Antitrypsin levels?
Low levels can be caused by genetic mutations, liver disease, or certain medications. If you have a family history of alpha-1 antitrypsin deficiency, this test may be recommended to check your levels.
How often should I get this test?
Your healthcare provider will determine how often you need this test based on your medical history, symptoms, and risk factors. For those with a known deficiency, monitoring may be done regularly.
Can diet or lifestyle changes affect this test result?
While diet and lifestyle factors like smoking can influence lung health and may indirectly affect Alpha-1 Antitrypsin levels, the test itself does not require dietary restrictions. Smoking should be avoided to prevent lung damage.
  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