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Cardiolipin Antibody, Qualitative (IgG)

Published: August 9, 2026Updated: August 15, 2026

This test detects the presence of antibodies against cardiolipin, a phospholipid found in cell membranes. It is often used to help diagnose conditions like lupus anticoagulant or antiphospholipid syndrome.

Quick summary

["This test helps identify certain autoimmune conditions that may affect blood clotting."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 15, 2026Editorial policy

Key facts at a glance

LOINC
20424-8
Short code
CARDIG
Synonyms
Cardiolipin IgG Ser-Imp
Category
chemistry
Sample
serum
Container
Serum separator tube (SST) — red-top or gold-top tube with gel separator; alternatively, plain red-top tube
Units
N/A
Ref low
10
Ref high
14
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
Enzyme-Linked Immunosorbent Assay (ELISA)
CPT
86147
SNOMED
44389003
Specimen volume
1 mL serum (minimum 0.5 mL)
Stability
Room temperature: 8 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C or below): 30 days. Avoid repeated freeze-thaw cycles. For long-term storage, aliquot and freeze at -20°C or colder.
Hemolysis max
100
Lipemia max
100
Icterus max
50
TAT
24–72 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order this test if you have symptoms like unexplained blood clots, recurrent miscarriages, or other signs of an autoimmune disorder. It can also be part of a broader evaluation for conditions like lupus or antiphospholipid syndrome.

What Does a Positive Result Mean?

A positive result suggests the presence of cardiolipin antibodies, which may indicate an increased risk of blood clotting problems or other autoimmune activity. However, this alone does not diagnose a specific condition; further testing and clinical correlation are needed.

What to Expect Before the Test

No special preparation is usually required, but you may be asked to fast or avoid certain medications for a short time. Bring any relevant medical records or medications you’re currently taking to your appointment.

What Happens During the Test?

A blood sample will be drawn from a vein in your arm. The sample is then tested for cardiolipin antibodies using an immunoassay method. The process typically takes a few minutes, and you may feel slight discomfort but no lasting effects.

Reference range

Negative: <10 GPL U/mL; Equivocal: 10-14 GPL U/mL; Positive: 15-40 GPL U/mL (Moderate); >40 GPL U/mL (High). Reference values vary by laboratory and assay manufacturer.N/A

Specimen: serum

No fasting required. Patients should be informed that antiphospholipid antibodies should be confirmed with repeat testing after a minimum of 12 weeks to establish persistence, as transient elevations can occur due to infections or medications.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Cardiolipin Antibody (IgG) Test

Frequently asked questions

Your healthcare provider may recommend this test if you have a history of blood clots, pregnancy complications, or other autoimmune symptoms. Cardiolipin antibodies can be linked to conditions that interfere with normal blood clotting, such as lupus anticoagulant, which may increase the risk of clotting disorders.
This test is qualitative, meaning it only tells whether antibodies are present (positive) or not (negative). It does not provide a specific quantity of antibodies, so results should be interpreted alongside clinical findings and other tests.
How long will it take to get my results?
Results are usually available within a few days to a week, depending on your lab’s processing time. Your healthcare provider will discuss the results with you during a follow-up visit.
Can I take anything before the blood draw?
While no specific medications or foods are restricted, avoid heavy meals or excessive alcohol before the draw to minimize discomfort. Always follow your provider’s instructions for best accuracy.
  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 15, 2026. · Read our editorial policy