The anti-dsDNA (anti-double stranded DNA) antibody test is a blood test that looks for antibodies to double stranded DNA.
The anti-dsDNA antibody test is a very specific test for Systemic Lupus Erythematosus (SLE). That’s because Anti-dsDNA antibodies aren’t found in any other autoimmune disorders other than SLE.
A strongly positive anti-dsDNA antibody test makes it very likely that a person has SLE. However, if the test is negative, it does not necessarily rule out SLE. About 30-50% of people with SLE have a negative anti-dsDNA antibody test.
Science Behind this Test
Anti-dsDNA antibodies are a type of autoantibody: an antibody produced by the immune system that targets something that the body’s own tissues are made of.
Anti-dsDNA attacks DNA (deoxyribonucleic acid), the basic building block that makes up our chromosomes. Our chromosomes contain our genes which are basically the instructions or blueprints to make all the proteins essential for body functions.
Why the anti-dsDNA test is done
The anti-dsDNA test is usually done after another test called an ANA (anti-nuclear antibody) test. This is a screening test for autoimmune diseases. It is not specific to SLE. When the ANA test is positive and SLE is suspected, an anti-dsDNA test is ordered to help confirm the diagnosis.
Anti-dsDNA test results
The anti-dsDNA test’s results are important to consider because:
- It helps establish a diagnosis of SLE
- It can be used to monitor disease activity in a person with SLE since the levels of anti-dsDNA antibody can fluctuate
- If the anti-dsDNA levels are high, the disease may be active or there is a current or imminent disease flare
- If the anti-dsDNA levels are low, the disease may be “quiet” or less active