An abnormal result on an antinuclear antibody test means that the patient's blood contains antinuclear antibodies, which indicates an autoimmune reaction in the body. However, some healthy people also test positive for antinuclear antibodies, according to the Mayo Clinic.
An autoimmune reaction occurs when the immune system fails to distinguish between antigens and healthy body tissue, causing the body to produce antinuclear antibodies. These antibodies then attack the normal body tissue and organs causing changes in the functions of organs, damage to body tissues and abnormal growth of organs, says MedlinePlus. This causes a number of symptoms, such as fatigue, joint pain, rash, fever and a general ill feeling.
To test for an autoimmune disorder, a patient takes an ANA test, but a doctor can also order other tests, such as urinalysis or autoantibody tests. If the blood contains ANA, the patient receives an abnormal test result. This does not always indicate disease, since relatives of people with systemic lupus erythematosus can test positive for ANA even when they are healthy, says MedlinePlus.
If the patient is really ill, he could be suffering from myositis, Sjögren's syndrome, rheumatoid arthritis, systemic lupus erythematosus or chronic liver disease. The ANA test does not confirm the presence of a particular autoimmune disease, but it helps rule out some diseases, according to the Mayo Clinic. More tests are necessary to pinpoint a specific autoimmune disorder.