Anti-dsDNA antibodies

The upper limit depends on the method: 7, 10, 15 and 30 IU/mL are all in use, and some laboratories report only Negative, Equivocal or Positive, or a titre. Use the range printed by the lab.

Anti-dsDNA antibodies are antibodies against the double-stranded DNA inside the body's own cells. They are one of the more specific markers for lupus, and in people who have lupus the level tends to rise and fall with the activity of the condition, which is why it is often measured repeatedly. The test is usually run after a positive antinuclear antibody screen.

Doctors request it when looking at lupus, usually following a positive antinuclear antibody result, and repeat it over time in people who have lupus to follow the activity of the condition, particularly its effect on the kidneys.

• Lupus, particularly when active and when the kidneys are involved
• Some other autoimmune conditions, at low levels
• Some medicines, rarely, including some biologic medicines
• Some long-term infections, at low levels

• Negative is the usual finding in healthy adults; there is no lower limit
• Treatment of lupus with immune-suppressing medicines
• Quieter periods of the condition

• A low positive is found in a small number of healthy adults, particularly with the more sensitive methods
• Methods differ widely, so a number from one laboratory does not map onto another's range
• A recent infection can produce a temporary low positive

No fasting needed. In people with lupus the trend over time matters more than one value; in everyone else a single result is read alongside the ANA and complement levels.

Written by a UK consultant physician. Typical UK adult reference ranges; your laboratory's own printed range takes precedence.