Understanding ANA Blood Tests: What Do Your Results Mean?

The Antinuclear Antibody test, or ANA test, is a general screen for autoimmune disease. Antinuclear antibodies attack structures inside the cell nuclei, according to Merriam-Webster. A positive test may mean a patient's body is forming antibodies against itself, and a negative result indicates that is not likely.

Test Report

• A positive result is reported as a given dilution of the test sample showing a characteristic cell pattern as viewed by a microscope. An example would be "positive at 1:320 dilution with a homogenous pattern," according to Lab Tests Online.

Patterns

• Characteristic cell patterns are associated with different diseases, such as SLE (Systemic Lupus Erythematosis), sheumatoid arthritis and scleroderma. False positives may occur, especially in older patients. Positive results may also precede disease symptoms, according to Lab Tests Online.

Further Testing

• A doctor may order additional, more specific tests in a symptomatic person or decide to just wait and monitor someone without symptoms. Symptoms of autoimmune conditions can come and go. ANA results in the same patient may also change over time. Correct diagnosis should never depend solely on ANA results.