What this test measures
Indirect immunofluorescence on HEp-2 epithelial cells (commercial slides), reported as titre (1:80, 1:160, 1:320, 1:640, 1:1280+) and pattern (homogeneous, speckled, nucleolar, centromere, cytoplasmic, mitotic). ACR endorses IIF on HEp-2 as the GOLD STANDARD for ANA detection — more sensitive than ELISA-based ANA. Pattern + titre guides which specific autoantibodies to order next.
Why it matters
ANA is the first-line screening test for connective tissue disease (SLE, Sjögren's, scleroderma, MCTD, autoimmune myositis, autoimmune hepatitis). Indian Rheumatology Association and global guidelines endorse IFA over ELISA for SLE screening because of better sensitivity and the diagnostic clue provided by the pattern. Up to 20% of healthy adults have low-titre ANA (1:40–1:80), so interpretation depends on titre + pattern + clinical context.
How to prepare
No fasting required. Disclose pregnancy, current infection, recent vaccination, biotin supplements (stop 48–72h before — high-dose biotin interferes with some assays).
Markers & reference ranges
Reference ranges below are typical adult values. Your lab's reported range may differ slightly based on the assay platform and patient demographics — always read your report against the range printed on it.
| Marker | Normal range | If low | If high |
|---|---|---|---|
| ANA (HEp-2 IFA) (Titre)[1][2] | Negative (< 1:80) | < 1:80 — negative; CTD unlikely. Up to 20% of healthy adults have low-titre ANA without clinical disease. | 1:80 – 1:160 (low titre): borderline — clinical correlation; consider age, family history, symptoms. 1:320 – 1:640: moderate — investigate specific autoantibodies based on pattern. 1:1280+: high titre — strong suggestion of CTD; full autoimmune workup. Pattern guides next step: homogeneous → anti-dsDNA, anti-histone. Speckled → anti-ENA panel (Ro, La, Sm, RNP, Scl-70, Jo-1). Centromere → anti-centromere (limited scleroderma). Nucleolar → anti-Scl-70 / nucleolar autoantibodies (scleroderma). Cytoplasmic → mitochondrial, ribosomal, anti-Jo-1. |
ANA-IFA pattern → disease association
| Pattern | Associated antibody | Typical disease |
|---|---|---|
| Homogeneous | Anti-dsDNA, anti-histone | SLE, drug-induced lupus |
| Speckled | Anti-Sm, Ro, La, RNP, Scl-70 | SLE, Sjögren's, MCTD, scleroderma |
| Nucleolar | Anti-PM/Scl, anti-fibrillarin | Scleroderma, polymyositis |
| Centromere | Anti-centromere | Limited scleroderma (CREST) |
| Cytoplasmic | Anti-Jo-1, mitochondrial, ribosomal | Myositis (Jo-1), PBC (AMA), SLE (ribosomal) |
| Nuclear dot / mitotic | Anti-SP100, NuMA | PBC, SLE overlap |
Frequently asked questions
Is ANA the same as anti-dsDNA?
No — ANA is a broad screening test detecting any antibody to nuclear antigens. Anti-dsDNA is one specific subtype (anti-double-stranded DNA, highly specific for SLE). Positive ANA at high titre prompts ordering specific antibodies including anti-dsDNA.
Why does the pattern matter?
Different patterns correspond to different target antigens — homogeneous pattern → anti-dsDNA or anti-histone (SLE); speckled → anti-ENA (Ro, La, Sm, RNP, Scl-70); centromere → CREST scleroderma; nucleolar → scleroderma; cytoplasmic → myositis or PBC. Pattern saves time and money on follow-up testing.
I have a positive ANA but feel fine — should I worry?
Up to 20% of healthy adults have low-titre ANA (1:40–1:80) without any disease. Higher titres (1:320+), specific patterns, or symptoms warrant further workup. Discuss with a rheumatologist.
Will my biotin supplement affect this test?
Some ANA assays use biotin-based detection — high-dose biotin (5–10 mg as in hair / skin / nail supplements) can falsely lower the result. Stop biotin for 48–72 hours before testing.
Why is IFA preferred over ELISA?
IFA is more sensitive (catches more SLE) and provides the pattern, which guides next-step testing. ELISA-based ANA can miss certain autoantibodies and doesn't give pattern information.
How often should ANA be repeated?
Usually once for diagnosis. ANA titre and pattern don't reliably reflect disease activity — use anti-dsDNA, complement C3/C4, and clinical assessment for monitoring instead.
Related Autoimmune / Rheumatology tests
Tests commonly ordered alongside ANA SCREENING (IMMUNOFLUORESCENCE), or that help interpret an unexpected result.
Sources & references
- ACR — ANA Position Statement · accessed 2026-05-30T00:00:00.000Z
- ANA IIF International Consensus on Patterns · accessed 2026-05-30T00:00:00.000Z
- NIH MedlinePlus — ANA Test · accessed 2026-05-30T00:00:00.000Z
- Mayo Clinic Labs — ANA, IFA · accessed 2026-05-30T00:00:00.000Z
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