Cardiolipin Test - IgG

The cardiolipin IgG test is used to measure a type of antibody called IgG, which is produced by the immune system in the body. The test is also called the cardiolipin antibodies IgG test, anticardiolipin test, ACL antibody IgG test, and anticardiolipin antibodies IgG test.

Cardiolipin is a natural substance found mainly in the membrane (wall) that surrounds the mitochondria (small structures inside cells that help in producing energy). Usually, your immune system makes antibodies to fight against foreign substances. However, sometimes, the immune system produces antibodies that attack the body’s own cells and tissues, resulting in autoimmune disorders.

Elevated levels of antibodies against cardiolipin are seen in conditions such as antiphospholipid syndrome (a disorder in which the immune system makes antibodies that can cause abnormal blood clots to form in the blood vessels) and systemic lupus erythematosus (a disorder that leads to inflammation in connective tissues). Therefore, doctors use this test to diagnose and monitor autoimmune conditions and to guide proper treatment.

You may be advised to get the cardiolipin IgG test if you are experiencing the following symptoms of a disorder like antiphospholipid syndrome:

• Purplish discolouration of the skin
• Intense headache
• Open sores on the skin
• Pregnancy complication
• Anaemia (reduced haemoglobin in RBCs)
• Heart disease

The following categories of people are highly advised to get the cardiolipin IgG test:

• Pregnant women – Antiphospholipid syndrome in pregnancy is associated with complications such as pre-eclampsia (high blood pressure during pregnancy), early delivery, or pregnancy loss (miscarriage).
• Individuals with systemic lupus erythematosus – About 10–15 percent of patients diagnosed with systemic lupus erythematosus have antiphospholipid syndrome.
• Individuals with stroke (loss of blood to a part of the brain) – It has been observed that around 20% of strokes occurring in individuals younger than 50 years of age are associated with antiphospholipid syndrome.

The cardiolipin IgG test is used with other tests to help detect certain conditions, such as:

• Antiphospholipid syndrome – This is a condition in which there is an increased risk of forming abnormal blood clots in the blood vessels.
• Catastrophic antiphospholipid syndrome – In this condition, blood clots form within blood vessels in multiple organs.
• Systemic lupus erythematosus – This is a disease that causes inflammation in the cartilage and the linings of blood vessels throughout the body.
• Preeclampsia – This is a condition in pregnant women that causes high blood pressure.
• Miscarriage – This refers to the loss of pregnancy before the 20th week. It occurs because the foetus is unable to develop properly.

What to Expect Before the Cardiolipin-IgG Test

• No fasting is required for a standalone Cardiolipin-IgG Test. You can eat and drink normally. However, if it is part of a broader package that includes fasting tests, your doctor may advise fasting for 8-12 hours. Avoid strenuous exercise for 24 hours before the test, as intense physical activity can temporarily raiseCardiolipin-IgG levels and affect interpretation. Always inform your doctor about any ongoing medications.

What to Expect During the Blood Collection

• A phlebotomist cleans the skin with an antiseptic, then places an elastic band around your upper arm to make the veins easier to access. A small needle is inserted into the vein; you may feel a brief pinch. Blood is collected into a labelled tube in under a minute.

What to Expect After the Cardiolipin-IgG Test 

• A small cotton swab and bandage are placed over the site to stop any minor bleeding. You can return to normal activities immediately. Minor bruising is normal and disappears quickly. If dizzy, sit and rest for a few minutes. 

In the cardiolipin IgG test, the primary parameter being measured is:

• The amount of IgG antibodies against cardiolipin in the body.

The normal range for the cardiolipin IgG testis shown in the table below.

Note: The normal range might vary slightly depending on the laboratory and individual health conditions.

The table below provides a general interpretation of the cardiolipin IgG test results based on whether the levels are low or high.

Like any other medical test, this test also has some risks and limitations.

Risks:

• The cardiolipin IgG test is generally safe and involves minimal risk. You may experience slight pain when the needle is inserted or mild bruising afterwards, which usually resolves spontaneously.

Limitations:

• The diagnosis of antiphospholipid syndrome is sometimes difficult because its symptoms can be very different among different cases.
• The test usually cannot diagnose conditions on its own and is used in combination with lupus anticoagulant and anti-β2-glycoprotein I antibody tests.

Depending on your symptoms and results, your doctor might recommend certain additional tests to better understand your condition. These include:

• Lupus anticoagulant tests (IgG and IgM)
• Anti-β2-glycoprotein I (anti-β2GPI) antibodies (IgA, IgG, and IgM) test
• Hysteroscopy
• Progesterone test 
• Antinuclear antibody test
• Complete blood count (CBC)
• Chest X-ray
• Urinalysis