Antinuclear Antibodies (ANA)
A screening test for antibodies that target the body's own cell nuclei, used in evaluating autoimmune disease.
What it measures
ANA testing detects autoantibodies against components of the cell nucleus, usually by immunofluorescence (IFA) on HEp-2 cells. Positive results are reported with a titer (e.g. 1:80, 1:320) and a staining pattern.
Why it matters
A negative ANA makes systemic lupus very unlikely. A positive result supports autoimmune conditions such as lupus, Sjogren's syndrome, scleroderma and mixed connective tissue disease when symptoms are present.
What a high result can mean
Positive results occur with autoimmune diseases, autoimmune thyroid and liver disease, certain medications (hydralazine, procainamide, minocycline, TNF inhibitors), infections and some cancers. Low-titer positives (1:40 to 1:80) are found in about 10-30% of healthy people, especially women and older adults.
What a low result can mean
A negative result is normal and makes many systemic autoimmune diseases unlikely.
What affects the result
This is a qualitative/titer result rather than a numeric value. Higher titers (1:160 or above) are more likely to be meaningful. Positive screens are typically followed by specific antibodies (dsDNA, ENA panel).
Also called on lab reports
ANA, ANA Screen, ANA Screen, IFA, Antinuclear Antibodies, Antinuclear Antibody, ANA Direct, ANA by IFA, ANA Screen, IFA, with Reflex to Titer and Pattern
Related tests: Inflammation & Immunity
This page is educational and does not replace advice from a healthcare professional.