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Cardiolipin Antibody (IgM) – Phospholipid-Associated Autoantibody Test

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

This test measures the presence of IgM antibodies against cardiolipin, a phospholipid found in cell membranes. These antibodies may be linked to certain autoimmune conditions or blood clotting disorders.

Quick summary

["This test helps evaluate potential autoimmune or clotting risks by detecting unusual antibody activity against a common cell component."]

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

Key facts at a glance

LOINC
42733-6
Short code
CARDIOM
Synonyms
Cardiolipin IgM B2GP1 dep MoM Ser
Category
chemistry
Sample
serum
Container
Serum separator tube (SST) - red top with gel separator
Units
N/A
Ref low
0
Ref high
19.9
Critical range
— – 80 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
Immunoassay (ELISA) for beta-2 glycoprotein 1-dependent cardiolipin IgM antibodies, results expressed as Multiple of the Median (MoM)
CPT
86147
SNOMED
439171006
Specimen volume
1.0 mL serum (minimum 0.5 mL)
Stability
Room temperature: 8 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C or below): 6 months. Avoid repeated freeze-thaw cycles.
Hemolysis max
100
Lipemia max
50
Icterus max
50
TAT
24–72 hours
Order
routine

What This Test Measures

Cardiolipin is a phospholipid naturally present in cell membranes, including those in blood vessels. When the immune system mistakenly targets these molecules, it may produce antibodies like IgM cardiolipin antibodies. This test checks for their presence in your blood.

Why It Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like unexplained bruising, blood clots, or autoimmune conditions (e.g., lupus, antiphospholipid syndrome). It can also be part of screening for conditions affecting blood flow or clotting mechanisms.

Sample Collection and Preparation

A blood sample is drawn from a vein, typically in your arm. The blood is processed to separate serum (the liquid part after clotting). This serum is then tested for IgM antibodies against cardiolipin using a sensitive laboratory method.

What to Expect Before the Test

No special preparation is needed, but inform your provider about any medications (e.g., blood thinners) or recent illnesses that might affect results. Avoid alcohol or strenuous activity 24 hours before testing if instructed.

Reference range

< 20 MPL (negative); 20-39.9 MPL (low-positive); 40-79.9 MPL (medium-positive); ≥ 80 MPL (high-positive). Results expressed as Multiple of the Median (MoM) relative to a reference population median.N/A

Specimen: serum

No fasting required. Patient should be well-hydrated. Avoid testing during acute illness or inflammation as this may cause transient elevations.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Positive results may indicate an autoimmune response, potentially linked to conditions like antiphospholipid syndrome (APS), which can increase clot risk. While elevated antibodies don’t always mean a diagnosis, they may prompt further evaluation for underlying causes. Always discuss results with your provider.

Short name

IgM Cardiolipin Antibody

Frequently asked questions

What does a positive result mean?
A positive result suggests your immune system may be producing IgM antibodies against cardiolipin, which could signal an autoimmune or clotting-related process. This doesn’t diagnose a specific condition alone but may guide further testing or monitoring.
Can lifestyle changes affect this test?
Generally, lifestyle factors like diet or exercise don’t directly impact antibody levels in this test. However, certain medications (e.g., blood thinners) or infections may influence results, so always report any changes to your provider.
How often might I need this test?
Frequency depends on your symptoms and medical history. Your provider may order it periodically if you have a history of autoimmune disorders, clotting issues, or other related conditions. Follow their guidance for follow-up testing.
  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