What Is an ANA Blood Test Used For?

The ANA test, or antinuclear antibody test, is used as a primary test to help evaluate a person for systemic autoimmune disorders, according to Lab Tests Online. The test is most commonly used to diagnose systemic lupus erythematosus.

This test is typically ordered when a patient shows standard symptoms of systemic autoimmune disorders, or disorders that impact many organs and tissues in the body, states Lab Tests Online. Depending on the individual, this test may be used alone or together with other autoantibody tests.

During the test, lab technicians look for the ANA group of autoantibodies produced by the immune system, explains Lab Tests Online. These autoantibodies target substances found in the nucleus of the body’s cell, and ultimately cause severe tissue and organ damage.

The ANA test is also used along with a detailed personal history to diagnose or rule out other autoimmune disorders, including Sjogren syndrome, scleroderma and polymyositis, according to Lab Tests Online. In some rare cases, the ANA test is used for those with Raynaud syndrome, arthritis or dermatomyositis.

There are two different types of ANA tests, notes Lab Tests Online: immunoassay and indirect fluorescent antibody. For the immunoassay, the results are reported as a number. For the indirect fluorescent antibody, the results are reported as ratios, indicating the amount of ANA in the blood even after it was diluted.