To help diagnose and monitor lupus (systemic lupus erythematosus, SLE)
When you have a positive ANA test and signs and symptoms associated with lupus, such as persistent fatigue, pain in your joints and a red rash resembling a butterfly across the nose and cheeks; periodically used to assess disease activity in those who have been diagnosed with lupus
A blood sample drawn from a vein in your arm
Anti-double stranded DNA antibody (anti-dsDNA) is one of a group of autoantibodies called antinuclear antibodies (ANA). Normally, antibodies protect against infection, but autoantibodies are produced when a person's immune system fails to adequately distinguish between "self" and "non-self." They mistakenly attack the body's own healthy cells, causing tissue and organ damage. Anti-dsDNA specifically targets the genetic material (DNA) found in the nucleus of a cell, hence the name "anti-dsDNA." The anti-dsDNA test identifies the presence of these autoantibodies in the blood.
While anti-dsDNA may be present at a low level with a number of disorders, it is primarily associated with lupus. Lupus is a chronic inflammatory autoimmune disorder that can affect various tissues and/or organs of the body such as the kidneys, joints, blood vessels, skin, heart, lungs, and the brain. (For more on this, read the article on Lupus). The test for anti-dsDNA, along with other autoantibody tests, may be used to help establish a diagnosis of lupus and distinguish it from other autoimmune disorders.
One serious complication of lupus is lupus nephritis, a condition characterized by inflammation of the kidneys, which can lead to protein in the urine, high blood pressure, and kidney failure. It occurs when autoantibodies bind to antigens that have been deposited in the kidneys. In the evaluation of someone with lupus nephritis, a high level (titer) of anti-dsDNA is generally associated with ongoing inflammation and damage to the kidneys.
- How is the test used?
The anti-double stranded DNA (anti-dsDNA) test is used to help diagnose lupus (systemic lupus erythematosus, SLE) in a person who has a positive result on a test for antinuclear antibody (ANA) and has clinical signs and symptoms that suggest lupus.
Typically, an ANA test is the first test performed to evaluate an individual for an autoimmune disorder. While a positive ANA test is seen in about 95% of lupus cases, it may be seen in many other conditions as well. The anti-dsDNA test is fairly specific for lupus; however, only 65-85% of people with lupus may be positive; that is, a negative anti-dsDNA does not rule out lupus. If a person has a positive ANA, an anti-dsDNA test may be used to distinguish lupus from other autoimmune disorders that have similar signs and symptoms.
An anti-dsDNA test may be ordered along with a test for anti-Sm (Smith antibody), another antinuclear autoantibody associated with lupus, to help establish a diagnosis. The anti-Sm test may be ordered as part of an extractable nuclear antigen (ENA) panel. Depending upon clinical signs and the healthcare practitioner's suspicions, other autoantibodies may also be ordered to help distinguish between, and rule out, other autoimmune disorders. Examples include tests for histone antibody (drug-induced lupus) and antiphospholipid antibodies.
The anti-dsDNA test may be used to assess disease activity in a person who has been diagnosed with lupus. Those with lupus often have flare-ups in which symptoms worsen and then subside. An increased anti-dsDNA level may be seen prior to and during these flare-ups. In particular, this test may be used to monitor lupus nephritis, a serious complication of lupus that can cause kidney damage and inflammation. This can lead to protein in the urine, high blood pressure, and kidney failure. It occurs when the autoantibodies bind to antigens that have been deposited in the kidneys.
- When is it ordered?
An anti-dsDNA test is ordered when a person shows signs and symptoms that could be due to lupus and has had a positive ANA test, especially when the result of the ANA test presents as a "homogeneous" or "speckled" fluorescent pattern. (See the article on ANA for more on this.)
Examples of some signs and symptoms of lupus include:
- Muscle pain
- Arthritis-like pain in one or more joints (but no or little joint damage)
- Red rash that frequently resembles a butterfly across the nose and cheek areas (malar rash)
- Low-grade fever
- Persistent fatigue, weakness
- Skin sensitivity to light
- Hair and weight loss
- Numbness or tingling in the hands or feet
- Inflammation and damage to organs and tissues, including the kidneys, lungs, heart, lining of the heart, central nervous system, and blood vessels
The anti-dsDNA test may be ordered periodically to monitor progress of the disease or flare-ups in a person who has been diagnosed with lupus. It may be repeated when an initial test result is negative but clinical signs and symptoms persist and lupus is strongly suspected.
- What does the test result mean?
The results of an anti-dsDNA test are usually considered together with a person's medical history, signs and symptoms, and results of other autoantibody tests.
A high level of anti-dsDNA in the blood is strongly associated with lupus and is often significantly increased during or just prior to a flare-up. When the anti-dsDNA is positive and the person tested has other clinical signs and symptoms associated with lupus, it means that the person tested likely has lupus. This is especially true if an anti-Sm test is also positive.
In the evaluation of someone with lupus nephritis, a high level (titer) of anti-dsDNA is generally associated with ongoing inflammation and damage to the kidneys.
A very low level of anti-dsDNA is considered negative but does not exclude a diagnosis of lupus. Only about 65-85% of those with lupus will have anti-dsDNA.
Low to moderate levels of the autoantibody may be seen with other autoimmune disorders, such as Sjögren syndrome and mixed connective tissue disease (MCTD).
- Is there anything else I should know?
Anti-dsDNA tests may be performed using different assays. Many laboratories use an anti-dsDNA ELISA test (enzyme-linked immunoabsorbent assay), but other methods may also be used.
Anti-dsDNA is sometimes present with diseases such as chronic hepatitis, primary biliary cirrhosis, and infectious mononucleosis. It may also be seen in those taking drugs such as procainamide and hydralazine. It is not usually tested or monitored under these conditions.
In addition to testing for anti-double-stranded DNA, there is also an anti-single-stranded DNA (anti-ssDNA) test. This autoantibody is less commonly tested and is not strongly associated with lupus but may be seen with other autoimmune disorders.
ANA consists of a group of antinuclear antibodies. If an ANA test is negative, it indicates that the entire group is negative. Since anti-dsDNA is a member of this group, it does not need to be ordered separately when an ANA test is negative.
- Why might it take a long time to be diagnosed with lupus?
A healthcare practitioner must rely not only test results, but on clinical symptoms and the person's history for a diagnosis. Symptoms may be nonspecific and often come and go. Test results may not initially be positive for some of these autoantibodies due to the cyclic nature of autoimmune disorders. In some cases, it may take months or years to show a pattern that might suggest lupus or any of the other autoimmune diseases.
- If I have been diagnosed with lupus, will it ever go away?
There is no cure for lupus, but the symptoms and complications can be managed. Most people with the condition will experience flare-ups, but most will also have periods of few or mild symptoms.
- Will my anti-dsDNA ever go away?
No, once the autoantibody has been produced by the body, it will continue to be present. However, the concentration in the blood will vary over time and can be present at very low levels.
- Is there anything I can do to affect my anti-dsDNA level?
Autoantibodies do not respond to lifestyle changes because they reflect the presence and severity of an autoimmune process.
- Can the anti-dsDNA test be performed at my healthcare practitioner's office?
The test requires specialized equipment. Your sample will need to be sent to a laboratory that performs these tests.