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Alpha-1 Antitrypsin, Serum/Plasma — Nephelometry, Mass Concentration

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

Measures the amount of alpha-1 antitrypsin in blood to help evaluate inherited deficiency and conditions affecting the lungs or liver.

Quick summary

["This blood test measures alpha-1 antitrypsin, a protein that helps protect the lungs and liver."]

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

Key facts at a glance

LOINC
6771-0
Short code
A1AT SerPl Neph-mCnc
Synonyms
A1AT SerPl Neph-mCnc
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
nephelometry
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

What is this test?

This test measures the concentration of alpha-1 antitrypsin in serum or plasma. This protein is made by the liver and helps protect lung tissue from inflammation and damage.

Why might I need this test?

A doctor may order this test for unexplained chronic lung disease, recurring lung infections, or certain liver conditions. It may also be used when a family history suggests alpha-1 antitrypsin deficiency.

How is the test performed?

A blood sample is collected, and the laboratory measures alpha-1 antitrypsin using a nephelometric method. The result is reported as a mass concentration in the blood.

How do I prepare for the test?

No special preparation is usually required for this test. Follow any instructions from your healthcare professional, and tell the laboratory if you are pregnant or have recently received certain treatments, as these can affect some laboratory measurements.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Alpha-1 antitrypsin level

Frequently asked questions

What does alpha-1 antitrypsin do?
It is a protective protein made mainly by the liver. It helps limit inflammation and damage in the lungs and other tissues.
Is this the same as an alpha-1 antitrypsin deficiency test?
The blood level is often used to evaluate possible deficiency. Additional genetic testing may be needed to confirm a specific inherited variant.
Do I need to fast before this test?
Fasting is generally not required, but your healthcare professional or laboratory may provide specific preparation instructions. Certain medicines and medical treatments can influence the result.
  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