Cardiolipin Ab IgA

What is Cardiolipin Ab IgA?

Antibodies targeting a membrane phospholipid, tested with IgG and IgM as part of the antiphospholipid antibody panel.

Cardiolipin is a phospholipid found in cell membranes, and antibodies against it are among the markers used to evaluate antiphospholipid syndrome, a condition associated with increased clotting risk and pregnancy complications. The IgA isotype is less routinely tested than IgG or IgM and its independent significance is still being studied, though it may be considered in people with strong clinical suspicion despite negative IgG and IgM results. This test is often ordered when someone has experienced unexplained blood clots, recurrent pregnancy loss, or has an underlying autoimmune condition such as lupus. A positive result is typically confirmed with repeat testing weeks later, since transient positives can occur, for example after infection. As with other antiphospholipid markers, this result is one piece of a broader clinical and laboratory picture rather than a stand-alone diagnosis.

Tests often checked alongside this

• Cardiolipin Ab IgG — the isotype most strongly linked to clotting risk
• Cardiolipin Ab IgM — another isotype tested in the same panel
• Beta-2-Glycoprotein IgA, IgG, and IgM — related antiphospholipid antibodies
• ANA Pattern and ANA Titer — often checked in suspected lupus overlap

How this can show up in how you look and feel

• May be associated with a history of unexplained blood clots
• May be associated with recurrent pregnancy loss
• May be associated with migraine-like headaches
• May be associated with a mottled skin pattern (livedo reticularis)

What can affect this marker

• Sex
• Pregnancy
• Medications
• Infection
• Lab variability, including the need for repeat confirmatory testing

What to track over time

• Whether a positive result persists on repeat testing weeks later
• How results align with beta-2-glycoprotein antibody and lupus anticoagulant testing
• Whether monitoring is considered before or during pregnancy

What to ask your doctor

• Does this result need to be repeated to confirm a persistent finding?
• How does this relate to my beta-2-glycoprotein antibody results?
• Could this affect pregnancy planning or management?
• Should I be evaluated for antiphospholipid syndrome more broadly?

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