Antinuclear antibodies (ANA)

What it measures

Detects autoantibodies against nuclear components. It is the main screening test for systemic autoimmune rheumatic diseases, especially SLE.

Specimen and preparation

• Specimen: Serum
• Tube: Gold top

Reference range

Reference ranges differ between laboratories, methods and populations. Always use the range printed on your own lab report.

Causes of high values

• SLE (> 95% positive)
• Sjögren, systemic sclerosis, mixed connective tissue disease, myositis
• Autoimmune hepatitis, drug-induced lupus
• Low titres in healthy people, especially older women

Method

Indirect immunofluorescence on HEp-2 cells (titre and pattern); ELISA/CLIA screens

Good to know

Report pattern (homogeneous, speckled, nucleolar, centromere); a negative HEp-2 ANA makes SLE unlikely. Follow positives with anti-dsDNA and ENA.

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