Anti-dsDNA test explained (anti-dsDNA)

Anti-dsDNA are autoantibodies that the immune system mistakenly produces against double-stranded DNA, which sits in the nucleus of every cell. A healthy person's body usually does not produce these antibodies, or has very few of them. Anti-dsDNA is one of the most specific autoantibodies known in medicine — unlike the more general ANA test, a positive anti-dsDNA result is much more strongly linked with systemic lupus erythematosus (SLE). The test is most often done when ANA is already positive and more precise confirmation is needed, or when a person has already been diagnosed with SLE and the course of the disease is being monitored. According to MedlinePlus, changes in the anti-dsDNA titre are sometimes linked with disease activity, especially when the kidneys are affected (lupus nephritis), so doctors may repeat it over time together with complement (C3, C4) and urine tests. A positive result on its own does not confirm the diagnosis — it is assessed together with symptoms, other autoantibodies and the clinical picture.

• When the ANA test is positive and more precise confirmation is needed as to whether this could be systemic lupus erythematosus
• When there are symptoms typical of SLE — joint pain and stiffness, long-lasting tiredness, fever with no clear cause, a facial rash (butterfly-shaped), increased sensitivity to sunlight
• When there is chest pain on breathing deeply, hair loss, mouth ulcers, swollen lymph nodes or Raynaud's syndrome (fingers turning pale in the cold)
• To monitor the course of already diagnosed SLE and the response to treatment over time
• When kidney damage (lupus nephritis) is suspected in someone with SLE — together with urine tests and complement measures
• When headache, dizziness, confusion or memory problems of unclear cause appear together with other signs of SLE

A raised anti-dsDNA is considered one of the most specific markers linked with systemic lupus erythematosus, especially when typical symptoms are present as well. According to MedlinePlus, to confirm the diagnosis the doctor also assesses ANA, other antibodies, blood and urine tests, and sometimes a skin or kidney biopsy. Changes in the titre over time are sometimes linked with disease activity, especially kidney damage.

What can raise anti-dsDNA

• Systemic lupus erythematosus (SLE) — the most common and most specific cause
• Active SLE, especially with kidney damage (lupus nephritis) — according to MedlinePlus, in such cases the doctor also assesses complement (C3, C4) and urine measures
• More rarely, other connective tissue diseases, in which anti-dsDNA is found together with other autoantibodies

Symptoms that can accompany a raised result

• Joint pain, stiffness and swelling
• Fever with no clear cause
• Long-lasting tiredness
• A facial rash (butterfly-shaped)
• Increased skin sensitivity to sunlight
• Chest pain on breathing deeply
• Hair loss, mouth ulcers, swollen lymph nodes
• Headache, dizziness, confusion or memory problems
• Swelling of the legs (a possible sign of kidney damage)

What is usually assessed alongside a raised result

• ANA and other autoantibody tests (anti-Sm, anticardiolipin) for a more precise diagnosis
• Complement measures (C3, C4) and a urine test — to assess possible kidney damage
• Discussing symptoms and the clinical picture with a doctor, since a positive result alone does not confirm the diagnosis
• Repeating the test over time if SLE has been diagnosed — to assess disease activity
• If needed, a skin or kidney biopsy for further assessment

How anti-dsDNA differs from ANA

ANA is a broader, more sensitive but less specific test — it can be positive in various autoimmune diseases, or even in someone who is completely healthy. Anti-dsDNA is much more specific to systemic lupus erythematosus, so it is often ordered as an additional test after a positive ANA, for more precise confirmation.