Antinuclear Antibodies (ANA)
Anti-nuclear antibodies (ANA) are possible signs of autoimmune diseases, such as lupus, scleroderma, Sjögren’s syndrome, juvenile arthritis, or polymyositis 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 positive ANA blood test means autoantibodies are present, but it’s not a sure sign of an autoimmune disease.
What Are the Signs/Symptoms?
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 physician will interpret ANA results based on your clinical history. ANA is a popular initial test to evaluate 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 have lupus. Up to 15% of completely healthy people have a positive ANA test, so ANA tests don’t confirm diagnosis of lupus, or any autoimmune or connective tissue disease.
What Are Common Treatments?
A negative ANA test result means no autoantibodies are present. However, a positive ANA reading alone doesn’t indicate an autoimmune disease. ANA production is strongly age-dependent and increases in healthy people over age 65. A positive ANA reading may indicate a need for follow up blood tests, physical exam, and a review of history and symptoms. Additionally, some medications, viruses, and conditions (such as cancer) can cause a positive ANA.
Living with ANA
One positive ANA test result is not a sure sign of autoimmune disease, so you may not need any immediate treatment. Lab levels vary. Some autoantibodies are normal, so your positive result may not indicate any problem. Your rheumatology provider will determine what to do next, work with your provider and ask any questions you have about ANA.
Updated February 2023 by Lisa Carnago, FNP, and reviewed by the American College of Rheumatology Committee on Communications and Marketing.
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.