Anti-Nuclear Antibody (ANA): What does it mean if you test positive for an ANA?

As Rheumatologists, we often see patients for evaluation of a positive Anti-Nuclear Antibody (ANA). Sometimes, ANA tests may be reflective of an underlying autoimmune disease, but sometimes they are not. About 15% of the healthy population has an ANA test that is positive without any associated autoimmune disease. This percentage of positive ANA’s without clinically evident disease increases with age in healthy patients above the age of 65. An ANA test may also be positive for periods of time in healthy people who have had infections, or in people with malignancies. A Rheumatologist relies on a detailed history and examination and may check other types of lab tests to see if the ANA is related to an autoimmune disease or not. 

What is an Anti-Nuclear Antibody?

An antibody is a protein that is made by the immune system usually in response to an infection (it can also be made in response to vaccines). These antibodies help protect you. 

An Anti-Nuclear antibody however is an antibody that the immune system makes to target proteins in the nucleus of a cell. In this way, the immune system is identifying a normal “self” protein as foreign. Once ANA’s are made, they may signal the body to attack itself, leading to certain types of “auto” (self)-immune disease. However, as mentioned above, just having ANA positivity does not always lead to autoimmune disease. 

What autoimmune conditions may be associated with having an ANA positive test?

Autoimmune conditions including Systemic Lupus Erythematosus, Rheumatoid Arthritis, Sjogren’s Syndrome, Scleroderma, Inflammatory Myositis, Mixed Connective Tissue Disease may be associated with a positive ANA test. ANA’s may also be positive in diseases such as Inflammatory bowel disease and Hashimoto’s thyroid disease. The most important way of diagnosing these diseases is by a detailed history and examination. Other types of lab tests such as more specific types of ANA tests and complement tests/inflammation tests and urinalysis may also be obtained to increase suspicion of an autoimmune disease. 

Having a positive ANA test may cause worry in some individuals. We understand that concern. We are available to give you the time and care to answer your questions by conducting a detailed evaluation to understand if this positive test result will lead to a diagnosis of an autoimmune disease. In case it does, there are individualized therapies and management plans in place to best help you.