ANA (Antinuclear Antibodies)

Also written as: ANA, antinuclear antibody, FANA

Antibodies that react against the body's own cell nuclei, used as a screen for autoimmune conditions.

What it measures

Antibodies in the blood that bind to structures inside the nucleus, the control center of the body's own cells. Labs typically report a titer, which is how far the blood can be diluted and still show a reaction, and sometimes a staining pattern.

Why a doctor orders it

Ordered as a screening test when an autoimmune condition, such as lupus, is being considered. Typical prompts are unexplained joint pain, rashes, mouth ulcers, or persistent fatigue that does not have an obvious cause.

What is generally associated with a higher result

Broadly associated with autoimmune conditions such as lupus, Sjogren's syndrome, and scleroderma. A positive ANA is also common in entirely healthy people, particularly at lower titers and with increasing age, so a positive result on its own does not establish any disease.

What is generally associated with a lower result

A negative result is generally the expected finding, and it makes many, though not all, autoimmune conditions less likely.

Everyday things that move this number

Not every shift in a value reflects disease. These are ordinary factors known to affect this particular measurement:

Age - positive results become more common in older adults without any disease
Recent viral infections, which can cause temporary positivity
Some common medications
The laboratory method used, since different techniques can give different results
A family history of autoimmunity, which is linked to positivity in otherwise healthy relatives

Questions to take to your appointment

What titer and staining pattern were reported, and what do they suggest?
Do my symptoms make it worth checking more specific antibodies, such as anti-dsDNA or anti-Ro?
Could a recent infection or one of my medications explain a positive result?

Build a printable questionnaire with your own results →

Where to read more

MedlinePlus, from the US National Library of Medicine, publishes patient-facing pages on individual lab tests and is a reliable next stop: medlineplus.gov/lab-tests .

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