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Serum or plasma concentration of alpha-1 antitrypsin (A1AT) by immunoassay

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

This test measures the amount of alpha-1 antitrypsin, a protein that helps protect your lungs and liver from damage caused by enzymes released during inflammation.

Quick summary

["A1AT helps prevent lung diseases like emphysema and liver disorders; low levels may signal genetic risk or chronic conditions."]

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

Key facts at a glance

LOINC
14509-4
Short code
C trach Ag Cvx Ql IF
Synonyms
C trach Ag Cvx Ql IF
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
if
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 Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like persistent cough, shortness of breath, or unexplained liver issues. It’s also used to screen for genetic conditions like alpha-1 antitrypsin deficiency, which can affect both lungs and liver.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample, usually drawn from your arm. If you’re on blood thinners, let your provider know before the test.

What the Results Mean

Results help determine if your A1AT levels are within normal range or if they’re too low or high. Low levels may indicate genetic risk or conditions like chronic obstructive pulmonary disease (COPD) or liver disease.

Common Causes of Abnormal Results

Low A1AT levels can occur due to genetic mutations, chronic lung diseases, or liver problems. High levels may be linked to certain liver diseases or conditions like cirrhosis.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

A1AT Level

Frequently asked questions

What triggers a referral for this test?
A referral is often made if you have a family history of lung diseases like emphysema, chronic bronchitis, or liver conditions like cirrhosis. Symptoms such as persistent coughing, wheezing, or unexplained weight loss may also prompt testing.
How often should I get this test if I have a known genetic risk?
If you’ve been diagnosed with alpha-1 antitrypsin deficiency, your provider may recommend regular monitoring—typically every 1–3 years—depending on your symptoms and overall health. Follow-up tests help track changes in your condition.
Can diet or supplements affect A1AT levels?
Dietary changes alone typically don’t significantly alter A1AT levels, but certain medications (like some antibiotics or liver disease treatments) may influence results. Always discuss potential supplements or medications with your healthcare provider before testing.
  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