Alpha-1 Antitrypsin — Nephelometry, Mass Concentration
Measures alpha-1 antitrypsin, a liver-made protein that helps protect the lungs and other tissues from damage.
["This test measures alpha-1 antitrypsin levels, which can help evaluate inherited deficiency and certain liver or lung conditions."]
Key facts at a glance
- LOINC
- 12466-9
- Short code
- A1AT Amn Neph-mCnc
- Synonyms
- A1AT Amn Neph-mCnc
- Category
- liver
- Sample
- fluid
- Container
- Sterile tube
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- nephelometry
- Specimen volume
- 2-5 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h
- Hemolysis max
- 300
- TAT
- 4–24 hours
- Order
- routine
What is this test?
Alpha-1 antitrypsin, also called A1AT, is a protein made by the liver. It helps control inflammation and protects tissues, especially in the lungs.
Why might I need this test?
Your doctor may order this test if you have unexplained lung disease, liver abnormalities, or a family history of alpha-1 antitrypsin deficiency. It may also be used to monitor a person with low A1AT levels.
How is the test performed?
The laboratory measures A1AT in a patient sample using nephelometry, which detects light scattered by protein in the sample. The test is usually performed on serum or plasma separated from a blood sample.
How do I prepare for the test?
No special preparation is usually required, and fasting is generally unnecessary. Follow your healthcare provider's instructions and tell the laboratory if you have a recent infection or other illness, because inflammation can affect the result.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Low alpha-1 antitrypsin levels may indicate inherited A1AT deficiency, which can increase the risk of emphysema and liver disease. Levels can also fall during severe illness or other conditions that affect the liver. Elevated levels may occur with inflammation and can be associated with certain chronic liver conditions, so results should be interpreted alongside symptoms, examination findings, and other tests.
Short name
Alpha-1 antitrypsin (A1AT) test
Frequently asked questions
What does a low alpha-1 antitrypsin result mean?
Does an infection or inflammation affect this test?
Is this the same as alpha-1 antitrypsin genotyping?
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