What this test measures
IFA on HEp-2 substrate, reporting titre (1:80 through 1:2560+) and staining pattern (homogeneous, speckled, nucleolar, centromere, cytoplasmic, mitotic). Pattern + titre informs which specific autoantibodies should be ordered next.
Why it matters
First-line screening test for SLE, Sjögren's syndrome, systemic sclerosis, MCTD, polymyositis / dermatomyositis, and autoimmune hepatitis. ACR explicitly endorses IFA over ELISA-based ANA for SLE screening — better sensitivity and pattern information.
How to prepare
No fasting required. Random sample. Disclose pregnancy, recent infection, recent vaccination, immunosuppression, biotin supplements (stop 48-72h before).
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 by IFA (Titre + Pattern)[1] | Negative (< 1:80) | < 1:80 — negative; CTD unlikely. Up to 20% of healthy adults have low-titre ANA. | Positive (≥ 1:80) — clinical context determines whether to investigate further. High titre (≥ 1:320) with relevant clinical features warrants specific antibody panel (anti-dsDNA for SLE, anti-ENA for Sjögren / scleroderma / MCTD, anti-centromere for limited scleroderma). |
ANA-IFA pattern → next-step testing
| Pattern | Associated specific autoantibodies | Likely disease |
|---|---|---|
| Homogeneous | Anti-dsDNA, anti-histone, anti-nucleosome | SLE, drug-induced lupus |
| Speckled (coarse/fine) | Anti-ENA panel (Sm, RNP, Ro, La, Scl-70) | SLE, MCTD, Sjögren, scleroderma |
| Centromere | Anti-centromere antibodies | Limited scleroderma (CREST) |
| Nucleolar | Anti-PM/Scl, anti-fibrillarin, anti-Th/To | Diffuse scleroderma, polymyositis |
| Cytoplasmic | Anti-Jo-1, anti-mitochondrial, anti-ribosomal P | Myositis, PBC, SLE |
Frequently asked questions
How is this different from ANA by ELISA?
IFA on HEp-2 cells is the gold standard — more sensitive, gives pattern information, and recommended by ACR. ELISA-based ANA misses some patterns and is less sensitive.
How long does the test take?
Typically 1–2 working days. Microscope-read; some labs offer automated readers.
Can I be ANA-positive without any disease?
Yes — up to 20% of healthy adults, especially women and older people, have low-titre positive ANA (1:80–1:160) without any autoimmune disease. Higher titres or specific patterns warrant further evaluation.
What does HEp-2 mean?
Human Epithelial type 2 — a cell line derived from human laryngeal carcinoma that's used as the substrate for IFA. It has a large nucleus and is mitotically active, making nuclear and cytoplasmic patterns easy to visualise.
Should I get ANA before going to a rheumatologist?
Discuss with your GP first. If symptoms suggest CTD (joint pain, rash, fatigue, dry eyes/mouth, photosensitivity, Raynaud's), ANA screening is a reasonable first step before specialist referral.
Related Autoimmune / Rheumatology tests
Tests commonly ordered alongside ANA by IFA, or that help interpret an unexpected result.
Sources & references
- ACR — ANA Position Statement · accessed 2026-05-30T00:00:00.000Z
- ANA IIF International Consensus · accessed 2026-05-30T00:00:00.000Z
- Mayo Clinic Labs — ANA, IFA · accessed 2026-05-30T00:00:00.000Z
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