The ANA, or Antinuclear Antibody Test, identifies the presence of antinuclear antibodies (ANA) in the blood. ANA is a group of antibodies produced by the patient’s immune system when it fails to distinguish between ‘self’ and ‘non-self’. These autoantibodies may attack the body’s own cells, causing signs and symptoms such as tissue and organ inflammation, joint and muscle pain, and fatigue. The presence of ANA can be a marker of an autoimmune process and is associated with several autoimmune disorders.