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Beta-2-glycoprotein I (Protein S100A12) Antigen

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

This test measures the amount of a specific protein (β₂-GP1) in your blood. It may be used to assess certain autoimmune conditions or as part of broader diagnostic testing.

Quick summary

["This protein helps identify potential autoimmune disorders or monitor related treatments."]

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

Key facts at a glance

LOINC
21108-6
Short code
B2 Glycoprot1 IgA Ser-aCnc
Synonyms
B2 Glycoprot1 IgA Ser-aCnc
Category
glucose
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms or risk factors for autoimmune diseases, such as antiphospholipid syndrome (APS) or lupus. It may also be part of routine screening or follow-up for patients with known conditions affecting this protein.

What to Expect Before the Test

No special preparation is usually needed. You may have a blood sample drawn from a vein in your arm, similar to other blood tests. If you’re on blood thinners, let your provider know before the test.

How the Test Works

Blood is collected and analyzed to detect the presence and concentration of β₂-GP1. The method used may involve immunoassay techniques to measure its levels accurately.

Possible Results and Interpretation

Results are compared to a reference range specific to this protein. Elevated or low levels may signal underlying health concerns, but interpretation depends on clinical context and other test results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

β₂-GP1 is involved in immune responses and blood clotting. Abnormal levels may indicate autoimmune conditions, such as antiphospholipid syndrome, which can increase the risk of blood clots. It may also help diagnose or monitor conditions like systemic lupus erythematosus (SLE). Always discuss results with your provider for personalized insights.

Short name

Beta-2-Glycoprotein I (β₂-GP1) Antigen

Frequently asked questions

What Does an Abnormal Result Mean?
An abnormal result doesn’t diagnose a condition alone. It may prompt further testing or evaluation by your healthcare provider to understand the cause, such as autoimmune activity or other health factors.
Will This Test Affect My Treatment?
If this test is part of a broader diagnostic workup, your treatment plan may be adjusted based on the results. Always follow your provider’s guidance and ask about how these findings might influence your care.
How Often Should I Get This Test?
Frequency depends on your medical needs. Your provider will determine how often to repeat this test, especially if you’re being monitored for conditions linked to β₂-GP1 levels.
  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