Causes of positive antinuclear antibodies, or ANA, test results include autoimmune diseases and certain medications, according to WebMD. Certain infections that result from viruses may also cause positive ANA test results. The positive results indicate the presence of ANA in the blood.
Autoimmune diseases that may cause positive ANA tests include those that attack the connective tissue, such as systemic lupus erythematosus, rheumatoid arthritis, juvenile idiopathic arthritis, Raynaud's syndrome and scleroderma, notes WebMD. Autoimmune disorders that attack other body tissues and lead to positive ANA test results include Hashimoto's thyroiditis, hepatitis, idiopathic thrombocytopenia, hemolytic anemia and Addison's disease. Medications that may lead to positive ANA test results include tuberculosis medications, heart disease medications and hypertension medications.
The ANA test is a type of blood test that determines the level of the blood ANA, which are substances that attack the body tissues, explains WebMD. Although the test does not involve any special preparatory procedures, it is advisable for the patient to notify the doctor of any medications he is currently taking to avoid inaccurate results. The patient should also notify the doctor of any viral diseases he has.
Although an ANA test is useful, it is risky because it predisposes patients with clotting problems to excessive bleeding, says WebMD. It may also result in phlebitis, which is the inflammation of the vein as a result of blood draw.