Cardiolipin Antibody (ACL) –IgM Test

What is the Cardiolipin IgM test?

Cardiolipin is a unique phospholipid that is biosynthesized in the inner mitochondrial membranes. This phospholipid plays an important role in mitochondrial bioenergetic processes including the production of ATP. It interacts with multiple proteins, enzymes and metabolite carriers, taking part in a number of reactions and helping in the optimal performance of various compounds. Problems and abnormalities in the phospholipid can lead to mitochondrial dysfunction.

The antiphospholipid antibodies are specific antibodies produced by the body that are mistakenly directed against cardiolipin.  The immunoglobulin M (IgM) antibody is the largest among the five major types of immunoglobulins and is the first antibody that is created by the body to fight infections. The IgM antibody recognizes a large variety of pathogenic antigens and plays an important role in body immunity. When directed against cardiolipins, it can produce various adverse conditions in the system.

The three types of anticardiolipin antibodies are the IgG, IgA and IgM types and this particular test measures the level of IgM type antibodies in the blood. 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 ACL antibodies are often found along with the lupus anticoagulant (LA) antibody but can also be detected alone. The antibodies are often responsible for the abnormal formation of clots in veins and arteries which are known as phlebitis and arterial thromboses respectively. These clots can form anywhere in the body and can lead to serious conditions like stroke, gangrene, and heart attack.

The condition resulting from complications from antiphospholipid antibodies is called antiphospholipid antibody syndrome (APS). It can also lead to myocardial infarction, clot formation in heart valves termed as Libman-Sacks endocarditis, pulmonary emboli, pulmonary hypertension, and recurrent miscarriages.

Many patients with these antibodies have a particular symptom that generates purple or reddish lacy pattern just under the skin known as livedo. The high levels of IgM are often associated with autoimmune hemolytic anemia. This is a condition where the patient’s immune system attacks their red blood cells.

Various infections and ailments like leukemia, alcoholic cirrhosis, and solid-organ malignancies can also result in a higher level of the IgM antibody. A large percentage of the elderly population have these antibodies but hey remain healthy. In most cases, multiple tests are conducted and repeat tests are ordered after around 12 weeks. A continued presence of the antibodies at a higher percentage can indicate a more serious issue.

Why do I need to undergo a Cardiolipin IgM test?

Doctors generally order this test when the patients are affected by abnormal blood clotting, abnormal bleeding or recurrent miscarriages. In many cases, a prolonged result obtained on a blood clotting test is also a reason for this test to be ordered.It is also conducted on people with autoimmune diseases, such as lupus. The formation of blood clots can involve pain and swell in the extremities, shortness of breath or headaches. The signs and symptoms vary depending on the location of the clot. 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, it is termed as pulmonary embolism, a person may have symptoms such as:

– Shortness of breath accompanied by labored breathing
– Coughing along with the presence of blood in sputum
– Chest pain while breathing.
– An abnormally fast heart rate

The test is also conducted when a patient tests positive in an ANA test. For pregnant women who are affected by APS, the test is used to monitor the conditions of pregnancy to prevent risks. In general, the IgG and IgM tests are conducted first. If these tests are negative but clinical suspicions still exist, then the IgA cardiolipin antibody testing may be ordered.

How is a Cardiolipin IgM 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, the healthcare practitioner disinfects the area where the needle will be inserted with an antiseptic solution. Then an elastic band is tied in the upper arm to make the veins swell with blood, thus making them more visible.

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

The band around the arm is loosened and the needle is then slowly withdrawn. Some pressure is applied on the site through a small bandage 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. For an infant, the blood may be obtained by puncturing the heel with a small needle called a lancet, as the veins are not prominent.

Some patients might feel faint or lightheaded after the collection and may require additional care. Any tenderness or bruising around the collection site is generally cured within a few days. Chances of infection are rare but might happen in exceptional cases. Such conditions are to be reported to a medical practitioner at the earliest for the necessary treatment.

What is the price for the cardiolipin IgM test in India?

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

When will I get the test results?

In general, the turnaround time for the test is 48 hours but some laboratories may take more time as testing schedules can vary.

What is the normal range for a Cardiolipin IgM test?

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

Normal: < 12.5 MPL U/mL
Indeterminate: 5 – 20 MPL U/mL
Positive: > 20 MPL U/mL

The one MPL unit is 1 microgram of the IgM antibody. 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 background of the patient and also on the exact method used for the test. A normal or negative level indicates that the cardiolipin antibodies are not present or not present at a detectable level in the blood at that time.

In many cases, the antibodies can be present in a person’s blood temporarily due to an infection or drug, or in people without symptoms as they age.

The medium levels of the antibodies are judged along with the major symptoms though in most cases they are not clinically significant. When the levels are higher, the test is generally repeated after 12 weeks to confirm the presence of the antibodies. If the doctor suspects that you have lupus, further tests can be ordered. The following tests can be ordered additionally.

– A complete blood cell count
– Partial thromboplastin time and activated thromboplastin time which tests how the blood clots.
– The antinuclear antibody test for lupus
– Ultrasound or other imaging tests, to look for clots in your arteries or veins.

Do I need to fast for the Cardiolipin IgM test?

Fasting or any other restrictions are not necessary for this blood test.

What else do I need to know before I appear for the cardiolipin IgM test?

The following points can be kept in mind to get a clearer idea about the test and its 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.

– A single positive test result is not sufficient to meet the established serologic criteria for the exact diagnosis of APS syndrome and multiple tests spread over a period of time are needed.

– A single positive result does not indicate that you have lupus or any other autoimmune disease.

Can pregnant women undergo a Cardiolipin IgM test?

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

Is Cardiolipin IgM test possible for new-born babies?

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