Anti-Cardiolipin Antibody (IgG) – Serum Immunoassay
This test measures the presence of antibodies against cardiolipin, a phospholipid found in cell membranes. These antibodies may be linked to autoimmune conditions or other health concerns.
["This test helps assess potential autoimmune activity in your blood."]
Key facts at a glance
- LOINC
- 51813-4
- Short code
- CBURN2M
- Synonyms
- C burnet Ph2 IgM Ser IA-aCnc
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST, tiger top) or red-top clot tube; preferred Becton Dickinson Vacutainer or equivalent
- Units
- N/A
- Ref low
- 0
- Ref high
- 1
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 1–99 years
- Method
- Enzyme-linked immunosorbent assay (ELISA) or chemiluminescent immunoassay (CLIA) for detection of IgM antibodies directed against phase 2 antigen of Coxiella burnetii
- CPT
- 86638
- SNOMED
- 122585009
- Specimen volume
- 1.0 mL serum (minimum 0.5 mL); collect 3–5 mL whole blood
- Stability
- Room temperature: 8 hours; Refrigerated (2–8°C): 7 days; Frozen (-20°C or lower): 30 days; avoid repeated freeze-thaw cycles
- Hemolysis max
- 100
- Lipemia max
- 100
- Icterus max
- 50
- TAT
- 24–96 hours
- Order
- routine
What Is This Test Measuring?
Cardiolipin is a lipid (fat) molecule found in cell membranes, particularly in heart tissue. When your immune system mistakenly attacks these molecules, it produces antibodies called anti-cardiolipin antibodies. This test detects IgG antibodies against cardiolipin in your serum.
Why Might You Need This Test?
Doctors may order this test to investigate symptoms like unexplained blood clots, recurrent miscarriages, or autoimmune diseases (e.g., lupus, rheumatoid arthritis). It can also be part of a broader evaluation for conditions like antiphospholipid syndrome.
How Is the Test Performed?
A blood sample is drawn from a vein in your arm. The serum portion is then tested using an immunoassay method to measure IgG antibody levels against cardiolipin.
What Are Possible Results?
Results are typically reported as a ratio or concentration level. Elevated levels may suggest an autoimmune response, but they are not definitive on their own. Your doctor will consider clinical symptoms and other test results.
Reference range
Negative: <1:64 or <9 U/mL (method-dependent); Equivocal: 1:64–1:128 or 9–11 U/mL; Positive: ≥1:256 or >11 U/mL. Cutoff values vary by assay manufacturer. Phase 2 IgM antibodies are associated with acute Q fever infection.N/A
No fasting required. Acute phase specimen should be collected at least 2 weeks after symptom onset to allow for detectable IgM seroconversion. Convalescent specimen recommended 3–6 weeks later to demonstrate seroconversion or four-fold titer rise.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: Anti-Cardiolipin Antibodies and Health Risks
Short name
Anti-CL IgG
Frequently asked questions
What Does a High or Low Result Mean?
How Often Should I Get This Test?
Can This Test Be Done at Home?
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 15, 2026. · Read our editorial policy