Skip to content

Alpha-1 Antitrypsin, Serum/Plasma — Mass Concentration

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

This test measures the amount of alpha-1 antitrypsin protein in your blood. It can help evaluate inherited deficiency and certain liver or lung conditions.

Quick summary

["Alpha-1 antitrypsin levels help identify possible protein deficiency that may affect the lungs or liver."]

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

Key facts at a glance

LOINC
20422-2
Short code
Deprecated A1AT SerPl-mCnc
Synonyms
Deprecated A1AT SerPl-mCnc
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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?

Alpha-1 antitrypsin is a protein made by the liver that helps protect lung tissue from damage. This blood test measures the concentration of this protein in serum or plasma.

Why might I need this test?

Your doctor may order this test if you have unexplained chronic liver disease, persistent wheezing or shortness of breath, or a family history of alpha-1 antitrypsin deficiency. It may also be used to monitor someone who has a low level or an abnormal form of the protein.

How is the test performed?

A blood sample is collected, usually from a vein in your arm, and sent to a laboratory for analysis. The laboratory measures the amount of alpha-1 antitrypsin in the sample. Depending on the result, your doctor may recommend repeat testing or additional tests to evaluate the type of the protein.

How do I prepare for the test?

This test usually requires no special preparation. Tell your healthcare professional if you are pregnant or have recently received an infusion of blood products, because these can affect test results. Follow any specific instructions from your doctor or the laboratory.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Alpha-1 antitrypsin

Frequently asked questions

What does a low alpha-1 antitrypsin level mean?
It may indicate an inherited deficiency of the protein, which can increase the risk of lung disease and some liver problems. Your doctor can help determine whether the result is clinically significant.
Is alpha-1 antitrypsin testing the same as genetic testing?
No. The blood test measures the amount of the protein, while genetic testing evaluates inherited changes that may affect its production. Additional testing may be needed if the blood result is abnormal.
Does this test require fasting?
Fasting is generally not required for this test, although laboratory instructions can vary. Confirm any preparation requirements with your healthcare professional before the blood draw.
  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