APII243881242 - CME/CMLE - ANA / ENA Autoimmune Testing-APII243881242

APII243881242 - Educational Activity

Pdf Summary

This educational commentary by Marnie Imhoff, MA, MBA, MLS(ASCP)CM, provides an overview of antinuclear antibody (ANA) testing in autoimmune disease diagnosis. Autoimmune diseases arise when the immune system loses self-tolerance and attacks the body's tissues, causing chronic inflammation and organ damage. Over 80 autoimmune diseases exist, including systemic lupus erythematosus (SLE), Sjögren’s syndrome, and systemic sclerosis.<br /><br />ANA testing plays a crucial role in diagnosing these conditions. ANAs are autoantibodies targeting nuclear and sometimes cytoplasmic cell components and are detectable in autoimmune diseases but also found in 12%-20% of healthy individuals, especially older adults. Thus, ANA results must be interpreted alongside clinical symptoms and other lab tests.<br /><br />The gold standard ANA detection method is the indirect immunofluorescence assay (IIF) using HEp-2 cells. This semi-quantitative test identifies the presence of ANAs, their titer, and fluorescent staining patterns, which can indicate specific autoantibodies associated with particular autoimmune disorders. However, interpretation requires expertise, and automated systems are increasingly used to reduce subjectivity. Other methods include ELISA and multiplex immunoassays, which offer automation and reduced subjectivity but screen fewer autoantibodies.<br /><br />Following a positive ANA, additional tests identify specific autoantibodies such as anti-double-stranded DNA (anti-dsDNA) antibodies—highly associated with SLE and useful for monitoring disease activity—and extractable nuclear antigen (ENA) antibodies linked to various connective tissue diseases. Various assays (ELISA, line immunoassays, multiplex platforms) detect these with varying sensitivities and specificities.<br /><br />The commentary emphasizes the Choosing Wisely guidelines, advocating that ANA and ENA tests be ordered only when there is clinical suspicion of autoimmune disease to avoid false positives, unnecessary tests, cost, and patient anxiety.<br /><br />In summary, ANA testing is an essential but complex tool in autoimmune disease evaluation. Its effectiveness depends on appropriate test selection, interpretation considering clinical context, and adherence to guidelines to optimize patient care and outcomes.

Keywords

Antinuclear Antibody Testing

Autoimmune Diseases

Systemic Lupus Erythematosus

Indirect Immunofluorescence Assay

HEp-2 Cells

Autoantibodies

ELISA

Extractable Nuclear Antigen Antibodies

Choosing Wisely Guidelines

Autoimmune Disease Diagnosis