Cardiolipin Antibody (ACL) – IgA test

What is the Cardiolipin IgA test?

Cardiolipins are a type of phospholipid that are important constituents of the platelets and the cell membranes. They form around 20% of the composition of the inner mitochondrial membrane and play an important role in the functioning of the membrane-associated proteins. Cardiolipin antibodies are classified as autoantibodies that act against the body’s own cardiolipins.

They are generally associated with a condition called the phospholipid antibody syndrome. The IgA (immunoglobulin A) test detects the presence of the cardiolipin antibodies in the blood. The patients with this syndrome can be affected by arterial and venous thromboses, thrombocytopenia and also recurrent foetal loss.

These antibodies can also affect the body’s ability to control the clotting of blood. This often leads to the formation of irregular blood clots in the arteries and veins resulting in various complications.
These antibodies are also associated with autoimmune disorders, such as Systemic Lupus Erythematosus (SLE).

They are also found in patients who have acute infections like HIV or with cancers. In some cases, drug treatments with phenytoin, penicillin and procainamide can also result in the production of these antibodies.

Patients with cardiolipin antibodies and with specific symptoms, can be diagnosed with antiphospholipid syndrome (APS). APS can be primary or secondary and the secondary type can be linked with an autoimmune disorder. Around 30% to 40% of patients with SLE are tested positive with these antibodies.

There are three classes of cardiolipin antibodies, namely IgG, IgM and/or IgA, which are present in the blood. Among them, the IgG and IgM testing are done at first. In case the results are negative and the symptoms persist, the IgA testing is conducted after that.

In most cases, if the test comes out as positive, it is repeated after around 12 weeks to find out whether the results are persistent or temporary. In general, IgG antibodies are the most prevalent type while the IgA and IgM can either be found alone or in combination with the IgG. In many cases, the test is ordered along with the lupus anticoagulant testing.

They are also found in almost 20% of young patients with heart ailments like stroke. In addition, these antibodies are also associated with conditions like recurrent spontaneous abortion and with thrombotic complications in mothers shortly after giving birth. Since the test does not point out any particular disease, it can be given along with a number of other tests for an accurate diagnosis.

Why do I need to undergo a Cardiolipin IgA test?

This form of cardiolipin antibody testing is generally ordered when a patient has symptoms like the formation of blood clots with recurrence. The external signs and symptoms may vary, depending on the location of the clot. This may include pain and swelling in the extremities, acute stroke, shortness of breath or headaches. In case the clot is in the deep veins of the legs a person may have symptoms such as:

– Leg pain or tenderness, usually in one leg
– Leg swelling or oedema
– Discoloration of the leg

If the clot is affecting the lungs (pulmonary embolism), a person may have symptoms such as:

– Sudden shortness of breath, laboured breathing
– Coughing along with the presence of blood in sputum
– Chest pain while breathing.
– Rapid heart rate

In many cases, the presence of these antibodies can result in complications during pregnancy, resulting in foetal growth restriction and foetal loss. In such cases, repeated tests are ordered.

How is a Cardiolipin IgA test performed?

The test is simple and is performed by drawing a small blood sample from a vein. The drawing process is also called venipuncture as blood is drawn by puncturing a vein with a needle. Generally, the collection site is located on the inside of the elbow or the back of the hand. The process involves the following steps.

-The area where the needle will be inserted is disinfected by an antiseptic. An elastic band is tied in the upper arm to make the vein swell with blood, thus making collection easier.

-A needle is inserted into the vein and blood is drawn through it in an attached vial. You may feel moderate pain, or some stinging sensation as the needle is inserted.

-After the required volume of blood is collected, the band around the arm is loosened to remove the pressure. The needle is withdrawn gently and pressure is applied on the area to prevent any excess bleeding. The spot is then covered with a sterile bandage.

– Since the size of the veins and arteries vary from one person to the other, the collection process may be difficult for some and multiple punctures may be needed.

A throbbing sensation or some bruising around the puncture site can happen in some patients. Some patients might feel faint or lightheaded after the collection and may require additional care.

Any pain or bruising around the collection site is generally cured within a few days. Chances of infection or excessive bleeding from the site are rare but might happen in some exceptional cases which require special treatment.

What is the price for a Cardiolipin IgA test in India? 

The price for the test ranges between Rs 500 to Rs 1500 depending on the centre and the facilities.

When will I get the test results?

The test results are generally delivered within 48 hours but some laboratories may take more time.

What is the normal range for a Cardiolipin IgA test?

The test results can be marked as negative, intermediate or positive. The reference ranges vary slightly from one laboratory to the other. In general, IgA levels in the blood have the following reference range.

– Negative: < 20 U/mL
– Positive: 20 U/mL or greater

The results depend on various factors and the final interpretation of the same is to be done by a qualified physician.

What do the results mean?

A negative result indicates that the antibodies are not present in the blood at the period of time. Positive results can be dues to an infection or some specific drug consumption. Some infections that can raise the level of the antibodies in blood are syphilis, malaria, parasitic diseases and infectious mononucleosis.

The antibodies can also occur in people without symptoms as they age. Hence any intermediate levels of the antibodies are to be interpreted in relation to the signs, symptoms and other clinical information. In general, the presence of a low number of antibodies in a patient is not considered a serious condition unless there are major symptoms.

When the results indicate a high level of cardiolipin antibodies, the test is generally repeated after 12 weeks to confirm the consistency of their presence in the blood. If there is a continued presence of the antibody, then the doctor can order for other tests for the right diagnosis. Some of the tests that might be ordered include the following.

– A complete blood cell count
-Partial thromboplastin time and activated prothromboplastin time to check the blood clot formation.
– The antinuclear antibody test for lupus
– An ultrasound, to look for clots in the arteries or veins.

Do I need to fast for the Cardiolipin IgA test?

Fasting or any other restriction is not necessary for this test.

What else do I need to know before I appear for a Cardiolipin IgA test?

There are a few points that can be kept in mind before appearing for the test.

– Even though the cardiolipin antibodies are connected to lupus, a positive test does not mean that you have the condition. Further tests are needed for any confirmation.

– In some cases, the reagents used for a syphilis test contain phospholipids and they can generate a false-positive result in patients with cardiolipin antibodies.

– The presence of cardiolipin antibodies does not mean that the patient will develop recurrent blood clots or other associated complications. The test results will also not be able to predict the frequency or severity of any blood clots in the body.

-For a patient who has been tested positive during pregnancy, special care needs to be taken to ensure that the complications, if any, can be avoided. The right medical approach can allow women with these antibodies to deliver healthy babies.

Can pregnant women undergo a Cardiolipin IgA test?

The test can be conducted on a pregnant woman without any restrictions.

Is Cardiolipin IgA test possible for new-born babies?

The test can be conducted on new-borns if it is suggested by a medical practitioner.