Doctor's Assessment Included
Every result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.
Anti-Cardiolipin IgM
Anti-cardiolipin IgM completes the antiphospholipid panel. For older adults, complete APS screening helps explain unexplained thrombotic events.
What It Measures
This test quantifies IgM antibodies directed against cardiolipin. Results are reported in MPL units.
Why It Matters
Anti-cardiolipin IgM completes the antiphospholipid antibody profile. Isolated IgM positivity is less specific for APS and may occur transiently with infections, but persistent positivity contributes to APS diagnosis.
When to Test
Testing is typically ordered alongside anti-cardiolipin IgG and lupus anticoagulant as part of a complete APS evaluation.
Symptoms
Low Levels
A negative result is normal. In the absence of other positive antiphospholipid antibodies, no follow-up is required.
High Levels
Elevated anti-cardiolipin IgM may contribute to APS diagnosis when persistent and combined with clinical criteria. Isolated IgM elevation is less predictive of thrombosis than IgG.
Lifestyle Tips
The same recommendations as for anti-cardiolipin IgG apply. If APS is confirmed, long-term anticoagulation and specialist follow-up are typically recommended.
Frequently Asked Questions
Is IgM less important than IgG?
IgG is more strongly associated with thrombotic events. However, IgM remains a diagnostic criterion and should be tested as part of the complete panel.
Can infections cause false-positive IgM?
Yes. Various infections can transiently elevate anti-cardiolipin IgM. This is why confirmation at 12+ weeks is required for APS diagnosis.
Do I need all three tests for APS diagnosis?
APS diagnosis requires at least one of three antibodies (anti-cardiolipin IgG/IgM, anti-beta2-glycoprotein I IgG/IgM, or lupus anticoagulant) to be persistently positive.