The anti-double stranded DNA (anti-dsDNA) tests are used to help diagnose and monitor lupus, also called systemic lupus erythematosus or SLE, a chronic inflammatory autoimmune disorder in which the immune system mistakenly targets the body’s own cells and tissues.
Your doctor may order an anti-dsDNA if you have a positive antinuclear antibody (ANA) test 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. Anti-dsDNA tests are also periodically used to assess disease activity in people who have already been diagnosed with lupus.
Purpose of the test
The anti-dsDNA test helps diagnose lupus if you have a positive result on a test for ANA and have clinical signs and symptoms that suggest lupus.
Typically, an ANA test is the first test performed to evaluate if you have 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 but only 65-85% of people with lupus may be positive so a negative anti-dsDNA does not rule out lupus.
If you have a positive ANA, an anti-dsDNA test may be used to distinguish lupus from other autoimmune disorders that have similar signs and symptoms.
To help establish a diagnosis, an anti-dsDNA test may be ordered along with a test for anti-Sm (Smith antibody), another ANA associated with lupus. The anti-Sm test may be ordered as part of an extractable nuclear antigen antibodies (ENA) panel.
Depending upon clinical signs and the health care 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 if you have 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.
What does the test measure?
Anti-dsDNA specifically targets the genetic material (DNA) found in the nucleus of a cell, identifying the presence of these autoantibodies in the blood.
Anti-dsDNA is one of a group of autoantibodies called ANA. Normally, antibodies protect against infection, but autoantibodies are produced when your immune system fails to adequately distinguish between “self” and “non-self.” They mistakenly attack your body’s own healthy cells, causing tissue and organ damage.
While anti-dsDNA may be present at a low level with a number of disorders, it is primarily associated with lupus. A chronic inflammatory autoimmune disorder, lupus can affect various tissues and/or organs of the body such as the kidneys, joints, blood vessels, skin, heart, lungs, and the brain.
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 marked 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.
When should I get this test?
An anti-dsDNA test is ordered if you’re showing signs and symptoms that could be due to lupus and have had a positive ANA test, especially when the ANA test result presents as a “homogeneous” or “speckled” fluorescent pattern.