Why it's done

Many rheumatic diseases have similar signs and symptoms — joint pain, fatigue and fever. While an ANA test can't confirm a specific diagnosis, it can rule out some diseases. And if the ANA test is positive, your blood can be tested for the presence of particular antinuclear antibodies, some of which are specific to certain diseases.

Aug. 03, 2017
References
  1. Antinuclear antibodies (ANA). American College of Rheumatology. https://www.rheumatology.org/I-Am-A/Patient-Caregiver/Diseases-Conditions/Antinuclear-Antibodies-ANAhttp://www.rheumatology.org/Practice/Clinical/Patients/Diseases_And_Conditions/Antinuclear_Antibodies_%28ANA%29/. Accessed June 7, 2017.
  2. Bloch DB. Measurement and clinical significance of antinuclear antibodies. https://www.uptodate.com/contents/search. Accessed June 7, 2017.