Serum/plasma concentration of high molecular weight alpha-1 antitrypsin (A1AT) by immunoturbidimetric method
This test measures the level of a protein called alpha-1 antitrypsin (A1AT) in your blood. A1AT helps protect your lungs and liver from damage caused by enzymes released during inflammation.
["This test helps assess your risk for lung diseases like emphysema or liver problems over time."]
Key facts at a glance
- LOINC
- 94429-8
- Short code
- HLA class II Ab.IgG low risk SerPl FC
- Synonyms
- HLA class II Ab.IgG low risk SerPl FC
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- flow-cytometry
- CPT
- 82784
- 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 healthcare provider may order this test if you have a family history of lung diseases, liver issues, or if symptoms like chronic cough, shortness of breath, or unexplained fatigue appear. It’s also used in monitoring conditions like alpha-1 antitrypsin deficiency.
What to Expect Before the Test
No special preparation is needed, but you may be asked to fast for 8–12 hours before the blood draw if your test involves a fasting sample. Wear a loose shirt for easy access to your arm.
During the Test
A healthcare professional will insert a small needle into your vein (usually in your arm) to draw blood. You may feel a brief pinch, but it usually doesn’t cause discomfort. The process takes about 5 minutes.
After the Test
You can resume normal activities immediately. Apply gentle pressure to the site to stop any bleeding, and avoid rubbing it. Check with your provider if you experience excessive swelling or pain.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Low levels of high molecular weight A1AT may indicate an inherited condition called alpha-1 antitrypsin deficiency, which can lead to lung diseases (like chronic obstructive pulmonary disease) or liver cirrhosis. High levels may be seen in certain inflammatory or liver diseases, but further evaluation is needed to interpret results accurately.
Short name
A1AT High Molecular Weight
Frequently asked questions
What does a low result mean?
How long does it take to get results?
Can I eat or drink before this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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