double stranded DNA Ab

The double stranded DNA Ab (dsDNA Ab) test is used in support of a diagnosis of systemic lupus erythematosus (SLE) and distinguishes it from other autoimmune disorders. The test is typically ordered following a positive ANA test in people who have clinical signs that suggest SLE. It may be ordered along with another autoantibody panel associated with SLE, the ENA. Depending upon clinical signs and the doctor's suspicions, additional autoantibodies may be ordered to help distinguish between, and rule out, other autoimmune disorders.

The dsDNA Ab test may be used to monitor disease activity in a person who has been diagnosed with SLE. Those with SLE often have flare-ups where symptoms worsen and then die down. Increased anti-dsDNA levels may be seen prior to and during these flare-ups.

A dsDNA Ab test is ordered when a person shows signs and symptoms that could be due to SLE AND has had a positive ANA test, especially when the ANA presents as a "homogeneous" or "speckled" fluorescent pattern. (See the article on ANA for more on this.) SLE is strongly associated with a positive ANA, which is seen in almost 100% of SLE cases. However, a positive ANA is seen in many other conditions whereas a positive dsDNA Ab is fairly specific for SLE. Since dsDNA Ab is more specific for ANA, the test will not usually be ordered when the ANA is negative. There are several methods of detection of dsDNA antibodies which have different reliabilities though some patients may only make antibodies detectable by one assay.

Some signs and symptoms of SLE 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)
• Fever
• Persistent fatigue
• Sensitivity to ultraviolet light
• Hair and weight loss
• Inflammation and damage to organs and tissues, including the kidneys, lungs, heart, lining of the heart, central nervous system, and blood vessels

The dsDNA Ab test may be ordered periodically to monitor disease progression or flare-ups in a person who has been diagnosed with SLE. It may be repeated when an initial test result is negative but clinical signs and symptoms persist. 

The result of an dsDNA Ab test is usually considered together with a person's medical history, signs and symptoms, and results of other autoantibody tests.

A high level of anti-dsDNA is strongly associated with SLE and is often significantly increased during or just prior to an SLE flare-up. If the dsDNA Ab test is positive and the person tested has other clinical signs associated with SLE, then is it likely that she has SLE. This is especially true if an anti-Sm test is also positive. In Australia, the anti-Sm test is very rarely positive (less than 5% of SLE patients).

A very low level of anti-dsDNA is considered negative but does not exclude a diagnosis of SLE. Only about 50-60% of those with SLE will have anti-dsDNA measured by one assay, though when assays are combined, up to 80% and perhaps with three or four different assays, 100% of SLE patients may be positive. Low to moderate levels of the autoantibody may be seen with other autoimmune disorders, such as Sjögren syndrome and mixed connective tissue disease (MCTD) and may be induced by some drugs such as TNF inhibitors. dsDNA Ab tests are semi-quantitative and may be performed using different assays. Many laboratories use an dsDNA Ab radioimmunoassay though more modern enzyme immunoassays are as reliable if not better. Many ELISA tests are not completely reliable.

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 double stranded DNA antibodies (anti-dsDNA), there is also an anti-single-stranded DNA test. This autoantibody is less commonly tested and is not strongly associated with SLE but may be seen with other autoimmune disorders.

A doctor must rely not only on test results, but on clinical symptoms and the person's history for diagnosis. Symptoms may be nonspecific and often come and go. Test results may not initially be positive for 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 SLE or any of the other autoimmune diseases.

There is no cure for SLE, 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.

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.

Autoantibodies do not respond to lifestyle changes because they reflect the presence and activity of an autoimmune process.

The test requires specialised equipment. Your sample will need to be sent to a laboratory that performs these tests.

Autoantibody testing is only necessary when a person shows symptoms that suggest an autoimmune disorder. Most people will never need to have an dsDNA Ab test performed.