The Test Sample
What is being tested?
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 the autoantibodies bind to antigens and become 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 sample collected for testing?
A blood sample is obtained by inserting a needle into a vein in the arm.
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.