Laboratory Test Reference Guide

300uL Serum

Chilled

If the screen is positive, further testing for individual antibodies against nuclear antigens will be tested (see ENA Identification).

Antigens used in the screen are Ro-52, Ro-60, SSB, Sm, RNP, Scl70, Jo-1, Pm/Scl, centromere, Mi-2, Ku, Th/To, ribosomal-P, PCNA, RNA Pol III and dsDNA.

• Don’t test ANA sub-serologies (or ENA antibodies) without a positive ANA and clinical suspicion of immune-mediated disease.
• Don’t repeat a confirmed positive ANA in patients with established connective tissue disease including JIA or systemic lupus erythematosus.

ANA should only be performed when there is a high index of suspicion for a connective tissue disease as the test is not specific and can be positive in other situations such as organ specific autoimmune disease, infection and malignancy. In addition it can be positive in healthy individuals for more than 10 years before the development of a connective tissue disease.  Indiscriminate testing frequently leads to unnecessary additional testing, medical assessment and patient anxiety, and should be avoided.

ANA and ENA results do not usually change significantly with treatment and repeat testing is therefore not useful unless there has been a change in the clinical picture suggesting evolving disease. 

The laboratory will not repeat ANA or ENA tests within 12 months without SMO discussion.

• Do not repeat ANA within 12 months of previous tests unless the result does not fit the clinical picture or there has been evolution in the clinical picture.   
• Do not repeat ENA testing unless there has been a change in the clinical picture.