A positive ANA test means that autoantibodies are present and could mean that an autoimmune disease is present. The immune system produces proteins called antibodies. Antibodies are created by white blood cells and help our bodies fight off germs in the body. When germs are recognized in the body, antibodies recruit other proteins and cells to help fight off the infection. This fight is called inflammation.
Sometimes our antibodies make a mistake and fight off the wrong blood cells which creates autoantibodies. Autoantibodies cause the body to attack itself which can lead the body to create large amounts of antinuclear antibodies (ANAs). A large amount of ANAs can be a sign of an autoimmune disease such as lupus, scleroderma, Sjogren’s syndrome, polymyositis/dermatomyositis, missed connective tissue disease, drug-induced lupus, Hashimoto thyroiditis, inflammatory bowel disease and autoimmune hepatitis. Although ANAs can indicate the presence of an autoimmune disease, up to 30% of healthy kids may have a positive ANA. It may be important for a rheumatologist to determine whether further testing is needed based on symptoms.
The most popular test for ANAs is a blood test called the fluorescent antinuclear antibody test (FANA). The FANA blood test is when fluorescent-labeled antibodies are viewed on a glass slide under the microscope and determine the pattern and strength of the fluorescence.