Beta-2-glycoprotein I (Protein S Antigen) Antibody, Serum
This test measures antibodies against a protein called beta-2-glycoprotein I (Beta-2-GPI), which can be linked to certain autoimmune conditions. These antibodies may increase your risk of blood clots or other complications.
["This test helps assess potential autoimmune risks related to blood clotting disorders."]
Key facts at a glance
- LOINC
- 110011-4
- Short code
- B2 Glycoprot1 Ab Msmt Ser
- Synonyms
- B2 Glycoprot1 Ab Msmt Ser
- Category
- glucose
- 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
Why This Test Might Be Ordered
Your healthcare provider may recommend this test if you have symptoms or risk factors for autoimmune conditions, such as recurrent blood clots, unexplained miscarriages, or lupus-related clotting issues. It may also be used to monitor treatment progress in patients with known autoimmune disorders.
What to Expect Before the Test
No special preparation is needed. You’ll provide a blood sample, usually drawn from your arm. The test involves a small needle, and you may feel a brief pinch. If you’re nervous, let your provider know so they can help you relax.
What the Test Measures
The test detects the presence of antibodies against beta-2-glycoprotein I, a protein involved in blood clotting regulation. High levels may suggest an autoimmune response that could affect blood vessel function.
How the Results Are Interpreted
Results are compared to a reference range for your age and health status. Elevated levels may indicate an increased risk of autoimmune-related clotting disorders, but they don’t diagnose a condition alone. Your provider will discuss the meaning with you based on your medical history.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Beta-2-GPI antibodies are associated with antiphospholipid syndrome (APS), a condition where the immune system mistakenly targets proteins in blood clots. This can lead to clotting in veins or arteries, increasing risks for stroke, heart attacks, or pregnancy complications. While not all positive results mean you have APS, they warrant further evaluation to rule out underlying autoimmune activity.
Short name
Beta-2-GPI Antibody (Antiphospholipid Antibody)
Frequently asked questions
What does a positive result mean?
Can lifestyle changes affect this test?
How often should I get this test?
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