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Alpha-1 Antitrypsin Phenotype, Serum/Plasma

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

This blood test identifies the different forms, or variants, of alpha-1 antitrypsin protein in your blood.

Quick summary

["The test helps determine whether you have an inherited variant of alpha-1 antitrypsin that may affect lung or liver health."]

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

Key facts at a glance

LOINC
6770-2
Short code
A1AT Phenotyp SerPl IFE
Synonyms
A1AT Phenotyp SerPl IFE
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
immunofixation
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?

The alpha-1 antitrypsin phenotype test identifies the forms of alpha-1 antitrypsin protein present in your blood. These forms are inherited and are sometimes called alleles or genetic variants.

Why might I need this test?

This test may be ordered if an alpha-1 antitrypsin level is low, if there is a family history of alpha-1 antitrypsin deficiency, or if a lung or liver condition may be related to an inherited protein variant.

How is the test performed?

A blood sample is collected, and laboratory methods are used to determine which alpha-1 antitrypsin protein forms are present. The result is usually combined with an alpha-1 antitrypsin level and, when needed, genetic testing.

How do I prepare for the test?

No special preparation is usually required. Follow your healthcare professional's instructions and tell the laboratory if you are pregnant or have recently received a blood transfusion, because these factors can occasionally affect testing.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Alpha-1 Antitrypsin Phenotype

Frequently asked questions

Does this test diagnose emphysema or liver disease?
No. It identifies alpha-1 antitrypsin protein variants that may contribute to these conditions. Diagnosis and risk assessment require clinical evaluation and other laboratory tests.
Is genetic testing the same as the phenotype test?
No. The phenotype test identifies the protein forms in your blood, while genetic testing examines specific DNA variants. They may be used together when the result is unclear.
Will I need to repeat the test?
Most people do not need repeat testing because inherited alpha-1 antitrypsin variants generally remain the same throughout life. Your healthcare professional will decide if confirmation is needed.
  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