ANA testing should not be used to screen subjects without specific symptoms (e.g., photosensitivity, malar rash, symmetrical polyarthritis, etc.) or without a clinical evaluation that may lead to a presumptive diagnosis of SLE or other CTD, since ANA reactivity is present in many non-rheumatic conditions and even in “healthy” control subjects (up to 20%). In a patient with low pre-test probability for ANA-associated rheumatic disease, positive ANA results can be misleading and may precipitate further unnecessary testing, erroneous diagnosis or even inappropriate therapy.
Sources:
BC Guidelines. Antinuclear antibody (ANA) testing protocol [Internet]. 2013 Jun [cited 2017 May 5].
Kavanaugh A, et al. Guidelines for clinical use of the antinuclear antibody test and tests for specific autoantibodies to nuclear antigens. American College of Pathologists. Arch Pathol Lab Med. 2000 Jan;124(1):71-81. PMID: 10629135.
Solomon DH, et al. Evidence-based guidelines for the use of immunologic tests: Antinuclear antibody testing. Arthritis Rheum. 2002 Aug;47(4):434-44. PMID: 12209492.
Tozzoli R, et al. Guidelines for the laboratory use of autoantibody tests in the diagnosis and monitoring of autoimmune rheumatic diseases. Am J Clin Pathol. 2002 Feb;117(2):316-24. PMID: 11863229.