Which test is commonly used after a positive ANA to identify specific autoantibody groups?

Which test is commonly used after a positive ANA to identify specific autoantibody groups?

• A. Enzyme-linked immunosorbent assay (ELISA) for ENA panel
• B. Rheumatoid factor testing
• C. dsDNA antibody test
• D. Anti-Smith antibody test

Answer: (A)

When a positive ANA is found, the next step is to identify the specific autoantibody groups to narrow down which autoimmune disease is likely. The test that does this best is the ENA panel, usually run by an ELISA. This panel detects antibodies against extractable nuclear antigens such as Ro/SSA, La/SSB, Sm, RNP, Jo-1, Scl-70, and others. Each antibody pattern points toward different diseases (for example, Ro/SSA and La/SSB are common in Sjögren syndrome; Sm and RNP help differentiate SLE or mixed connective tissue disease; Scl-70 is linked to systemic sclerosis). So the ENA panel provides a broad, antibody-group-specific profile from a single follow-up test. Rheumatoid factor targets another disease area (rheumatoid arthritis) and doesn’t identify ENA antibody groups. The dsDNA antibody test and Anti-Smith antibody test are important individual markers, but they are parts of the broader ENA testing strategy; using them alone doesn’t give the comprehensive autoantibody profile that an ENA panel offers.

When a positive ANA is found, the next step is to identify the specific autoantibody groups to narrow down which autoimmune disease is likely. The test that does this best is the ENA panel, usually run by an ELISA. This panel detects antibodies against extractable nuclear antigens such as Ro/SSA, La/SSB, Sm, RNP, Jo-1, Scl-70, and others. Each antibody pattern points toward different diseases (for example, Ro/SSA and La/SSB are common in Sjögren syndrome; Sm and RNP help differentiate SLE or mixed connective tissue disease; Scl-70 is linked to systemic sclerosis). So the ENA panel provides a broad, antibody-group-specific profile from a single follow-up test.

Rheumatoid factor targets another disease area (rheumatoid arthritis) and doesn’t identify ENA antibody groups. The dsDNA antibody test and Anti-Smith antibody test are important individual markers, but they are parts of the broader ENA testing strategy; using them alone doesn’t give the comprehensive autoantibody profile that an ENA panel offers.