What this test measures
ANA-IFA (anti-nuclear antibody by indirect immunofluorescence) is the gold-standard method for detecting anti-nuclear antibodies. Your serum is layered onto HEp-2 cells (a human epithelial cell line) on a glass slide. If you have ANA, the antibodies bind to nuclear components of these cells, and a fluorescent-labelled anti-human IgG reveals the binding pattern under a microscope.
The result has two parts: a titre (the highest dilution at which fluorescence is still visible — 1:80, 1:160, 1:320, 1:640, 1:1280) and a pattern (homogeneous, speckled, nucleolar, centromere, nuclear dots, cytoplasmic, etc.). The International Consensus on ANA Patterns (ICAP) has standardised pattern names to help rheumatologists choose the right follow-up antibody panel.
Why it matters
ANA-IFA is more clinically informative than an ELISA-based ANA screen because the pattern points your doctor toward specific autoimmune diseases. Homogeneous patterns suggest anti-dsDNA / anti-histone (lupus, drug-induced lupus). Speckled patterns include anti-Smith, anti-RNP, anti-Ro/SSA, anti-La/SSB (lupus, MCTD, Sjögren). Nucleolar patterns suggest anti-Scl-70 (diffuse scleroderma). Centromere pattern is highly specific for limited scleroderma (CREST). Without the pattern, a positive ANA gives less direction.
In Indian clinical practice, ANA-IFA is the preferred confirmatory test when an ELISA ANA comes back positive, or when clinical suspicion of lupus is strong despite a negative ELISA screen. Titres ≥1:160 are generally considered clinically significant; titres of 1:40–1:80 are common in healthy people and need clinical correlation.
How to prepare
No fasting required. Continue normal medications. Mention any drugs known to cause drug-induced lupus (procainamide, hydralazine, isoniazid, methyldopa, minocycline, anti-TNF biologics) and recent viral infections.
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 Titre (Reciprocal dilution)[1][2] | Negative or < 1:80 | Negative or low titre (≤1:40) makes systemic autoimmune disease unlikely. About 5% of healthy people have a titre of 1:80; about 1–2% reach 1:160. | Titre ≥1:160 is considered clinically significant. Higher titres (1:640, 1:1280) increase the likelihood of true autoimmune disease and warrant a specific antibody panel and rheumatology referral. |
| ANA Pattern (Descriptive)[1][2] | Negative | Negative — no detectable nuclear fluorescence. | Pattern guides next-step antibody testing: homogeneous (anti-dsDNA / anti-histone), speckled (anti-ENA panel including Smith, RNP, Ro, La), nucleolar (anti-Scl-70, anti-PM-Scl), centromere (limited scleroderma), nuclear dot, cytoplasmic, etc. |
ANA-IFA pattern → next-step antibody panel
| IFA Pattern | Targets | Likely Disease |
|---|---|---|
| Homogeneous (AC-1) | Anti-dsDNA, anti-histone | SLE, drug-induced lupus |
| Coarse speckled (AC-5) | Anti-Smith, anti-RNP | SLE, MCTD |
| Fine speckled (AC-4) | Anti-Ro/SSA, anti-La/SSB | Sjögren, SLE, neonatal lupus |
| Centromere (AC-3) | Anti-centromere (CENP-B) | Limited scleroderma (CREST) |
| Nucleolar (AC-8/9/10) | Anti-Scl-70, anti-PM-Scl, anti-fibrillarin | Diffuse scleroderma, scleromyositis |
| Cytoplasmic speckled | Anti-Jo-1, anti-ribosomal P | Myositis, SLE |
| Nuclear dots | Anti-Sp100, anti-PML | Primary biliary cholangitis |
Frequently asked questions
What is the difference between ANA ELISA and ANA IFA?
ANA ELISA is a fast quantitative screen reported in units. ANA IFA is microscopy-based, gives a titre and a pattern, and is the gold standard. IFA is more informative for diagnosis but takes 2–3 days.
Is 1:80 titre worrying?
Not in isolation. About 5% of healthy adults — especially women and older people — have a titre of 1:80 without any autoimmune disease. Higher titres (≥1:160) with relevant symptoms are more concerning.
My pattern is "speckled" — what does that mean?
Speckled is the most common pattern. It includes several targets — anti-Smith, anti-RNP, anti-Ro, anti-La. Your doctor will order an "ENA panel" (extractable nuclear antigens) to pinpoint which antibody is responsible.
Does the titre change with treatment?
ANA titres can drop somewhat with effective immunosuppression but often remain positive. Doctors monitor disease activity using clinical scores, specific antibodies (anti-dsDNA, C3/C4) and end-organ markers — not by retesting ANA-IFA.
Can ANA become positive after COVID or other viral infections?
Transient low-titre ANA positivity can follow viral infections (including COVID-19). It usually fades over weeks to months. Persistent high titres warrant rheumatology follow-up.
How long does the report take?
ANA-IFA typically takes 48–72 hours because slides are read manually by a trained immunologist.
Related Autoimmune / Rheumatology tests
Tests commonly ordered alongside Anti Nuclear Antibodies (ANA), IFA, or that help interpret an unexpected result.
Sources & references
- NIH MedlinePlus — ANA Test · accessed 2026-05-30T00:00:00.000Z
- International Consensus on ANA Patterns (ICAP) · accessed 2026-05-30T00:00:00.000Z
- ACR — Position Statement on ANA Testing · accessed 2026-05-30T00:00:00.000Z
- Mayo Clinic Labs — ANA by IFA on HEp-2 · accessed 2026-05-30T00:00:00.000Z
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