Cardiolipin Antibody (ACL) –IgG Test

Last Updated December 20th, 2021

What is the Cardiolipin IgG test?

The antiphospholipid antibodies are specific antibodies that are directed against phosphorus-fat components called phospholipids. The phospholipids are mainly present in the cell membranes and the inner mitochondrial membranes of the body.

These antibodies are found in patients with various ailments including arterial and venous thrombosis, connective tissue diseases, syphilis, antiphospholipid syndrome, livedoid vasculitis, Behçet’s syndrome, systemic lupus erythematosus, and others. The anticardiolipin antibodies are often responsible for the abnormal formation of clots in veins and arteries which are known as phlebitis and arterial thromboses respectively.

The three types of anticardiolipin antibodies are the IgG, IgA and IgM types and this particular test measures the level of IgG type antibodies in the blood. Patients who have been diagnosed with an antiphospholipid antibody syndrome (APS) have an increased risk for ailments like stroke, thromboembolism, thrombocytopenia, myocardial infarction, and recurrent miscarriages.

The chance of these antibodies being at a higher level is also more for people with an autoimmune disease like lupus. In many cases, the lupus anticoagulant (LA) and anticardiolipin antibody (ACL) can be detected together in the blood of a patient.

For a person affected by lupus, the presence of these antibodies can create a problem even when the disease is in control. This is because of the fact that the risk of blood clot formations is independent of the disease activity. The antiphospholipid antibody syndrome can also occur in individuals who are unaffected by lupus.

Other risks that are involved with these antibodies include miscarriages or fetal loss, the formation of a clot on a specific heart valve termed as Libman-Sacks endocarditis, pulmonary emboli, and pulmonary hypertension. In many people, a red or purple pattern under the skin of the arms and the legs, termed as livedo, may indicate a presence of these antibodies.

In many cases, these antibodies are also detected in patients affected by infections like hepatitis C, malaria, Lyme disease, syphilis, and HIV. Ailments like leukemia, alcoholic cirrhosis, and solid-organ malignancies can also result in a higher level of these antibodies. There are a few therapeutic drugs that can also result in a higher level of these antibodies. In addition, a large percentage of the elderly population who are healthy can also have a higher percentage of these antibodies.

In most cases, repeat tests are ordered after around 12 weeks and a continued presence of the antibodies at a higher percentage can indicate a more serious issue. It is to be noted that this blood test for IgG antibodies does not point out any particular disease. Hence it is often ordered along with a number of other tests for an accurate diagnosis.

Why do I need to undergo a Cardiolipin IgG test?

Patients might need this test when they are affected by repeated scenarios of blood clotting, abnormal bleeding or miscarriages. In many cases, a prolonged result obtained on a blood clotting test is also a reason for this test to be ordered.

The external signs and symptoms of a blood clot may vary, depending on the location of the clot. This may include pain and swelling in the extremities, shortness of breath or headaches. The test is used in such cases to identify the exact nature of the problem. In case the clot is in the deep veins of the legs a person may have symptoms such as:

– Leg pain or tenderness which usually occurs in one leg
– Leg swelling or edema
– Discoloration of the leg
– If the clot is affecting the lungs which are termed as pulmonary embolism, a person may have symptoms such as:
– Sudden shortness of breath, labored breathing
– Coughing along with the presence of blood in sputum
– Chest pain while breathing.
– Rapid heart rate

The test is also conducted for SLE as higher levels of the antibody in them can result in a greater risk of diseases like arterial or venous thrombosis and thrombocytopenia. The test also helps to diagnose the condition and treatment efficacy of the patients with cardiolipin antibody syndrome. For pregnant women who are affected by this syndrome, the test is used to monitor the conditions of pregnancy.

How is a Cardiolipin IgG test performed?

The antibodies are generally detected from a blood sample through the method of solid-phase enzyme-linked immunosorbent assays (ELISA). The test is simple and is performed by drawing a small blood sample from a vein. Generally, the collection site is located on the inside of the elbow or the back of the hand. The process involves the following steps.

At first, an elastic band is tied in the upper arm to make the veins swell with blood, thus making them more visible. The healthcare practitioner disinfects the area where the needle will be inserted with an antimicrobial solution.

A needle is inserted into the vein and the required volume of blood is drawn through it in an attached tube or vial. A slight stinging or burning sensation is felt when the needle is inserted.

The band around the arm is loosened and the needle is then slowly withdrawn. Some pressure is applied on the site through a gauze or a cotton piece to prevent any excessive bleeding. The spot is then covered with a sterile bandage and the sample is sent to the laboratory for testing.

Since the size of the veins and arteries vary from one person to the other, the collection process may be difficult for some patients and multiple punctures may be needed. A throbbing sensation or some bruising around the puncture site can happen in some cases. 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. There is a mild chance of an infection occurring in the collection site or a condition where excessive bleeding may occur. Such cases are to be reported to a medical practitioner at the earliest for the necessary treatment.

What is the price for the cardiolipin IgG test?

The price for the test ranges between INR 400 to INR 1500 depending on the center and the facilities.

When will I get the test results?

In general, the results are delivered within 48 hours but some laboratories may take more time as testing schedules can vary.

What is the normal range for a Cardiolipin IgG test?

The reference ranges can vary depending on the laboratory and the exact method of testing. In general, the reference levels of IgG are mentioned below.

Negative: <15 GPL
Indeterminate: 15−20 GPL
Low-medium positive: >20−80 GPL
Positive: >80 GPL

Here one GPL unit refers to 1 microgram of IgG antibodies. The results should be interpreted by a qualified physician in order to make a correct diagnosis.

What do the results mean?

The test results can vary depending on the age, gender, health history of the patient and also on the method used for the test. A higher result does not necessarily indicate that you have a problem. A negative result indicates that your levels are normal. The medium levels of the antibodies are judged along with the major symptoms though in most cases they are not clinically significant.

For higher levels, the test is generally repeated after 12 weeks to confirm the presence of the antibodies. This allows the doctors to make an accurate diagnosis for lupus or cardiolipin antibody syndrome. In many cases, the IgG test is ordered along with a range of other tests for an accurate diagnosis. This may include one or more of the following.

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

Do I need to fast for the Cardiolipin IgG test?

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

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

The following points are to be noted for getting a clearer idea on the test procedure and the results.

– 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.

– Multiple tests should be done from the same laboratory for getting uniform results.

– The diagnosis of APS should not be based on a single result but on multiple tests spread over a period of time.

– For a patient who has been tested positive during pregnancy, special care needs to be taken to avoid any complications.

Can pregnant women undergo a Cardiolipin IgG test?

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

Is Cardiolipin IgG test possible for new-born babies?

The test can be conducted on new-borns as advised by a medical practitioner.


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