Antinuclear Antibodies (ANA)
Antinuclear antibodies (ANA) are possible signs of autoimmune diseases, such as lupus, scleroderma, Sjögren’s disease, juvenile arthritis, and dermatomyositis. White blood cells in the body’s immune system make antibodies to spot and attack foreign agents that cause infections or disease. Sometimes, antibodies target normal proteins in our body by mistake. This can trigger inflammation that leads to joint or tissue damage. These antibodies are called autoantibodies. Everyone has small amounts of autoantibodies. ANAs are one type of autoantibody. A negative ANA blood test result means no autoantibodies are present. A positive ANA blood test means autoantibodies are present, but it’s not a sure sign of an autoimmune disease.
Relationship to Disease Conditions
A doctor will view antibodies under a microscope and look for certain patterns and intensity. Some labs will report any titer above 1:160 as positive. Your doctor will interpret ANA test results based on your clinical history.
ANA is often used to test for lupus. More than 95% of people with lupus will test positive for ANA, so a negative ANA test may help exclude that diagnosis. However, only about 11-13% of people with a positive ANA test actually have lupus or any autoimmune or connective tissue disease. Up to 15% of completely healthy people have a positive ANA test.
ANA production is strongly age-dependent, and increases in healthy people over age 65. A positive ANA test may indicate a need for follow up blood tests, a physical exam, and a review of history and symptoms. Additionally, some medications, viruses, and conditions (such as cancer) can cause a positive ANA test.
Care/Management Tips
One positive ANA test result is not a sure sign of autoimmune disease, so you may not need any immediate treatment. Some autoantibodies are normal, so one positive ANA test result may not mean there is a problem. Your rheumatology provider will determine what to do next. Work with your provider and be sure to ask any questions you have about ANA.
Updated February 2025 by Howard Yang, MD, RhMSUS, and Laura E. Ray, MA, MLS, and reviewed by the American College of Rheumatology Communications and Marketing Committee.
This information is provided for general education only. Individuals should consult a qualified health care provider for professional medical advice, diagnosis and treatment of a medical or health condition.