Antinuclear antibodies (ANA)
Autoantibodies against components of the cell nucleus; screening test for suspected autoimmune disease
Also known as
Definition
Antinuclear antibodies (ANA) target components of the nucleus of the body's own cells. The ANA test is used as a screening test when symptoms could point to an autoimmune disease such as systemic lupus erythematosus, Sjögren's syndrome or scleroderma. A positive result alone is not a diagnosis: ANA are also found in many healthy people, more often with increasing age.
| Parameter | Value |
|---|---|
| Unit | Titer (e.g. 1:80) and fluorescence pattern |
| Reference Range | Reported as a titer, often in steps from 1:40 to 1:640, usually together with a pattern (such as homogeneous or speckled). The titer at which a lab reports a positive result varies; some only from 1:160. The assessment on your report is what counts, and your doctor interprets the result. |
Agree on your personal target range with your doctor.
↓ What a low value means
A negative result means that no antinuclear antibodies were found. An autoimmune disease is then less likely but not completely ruled out. A few ANA in the blood are normal. If a low titer is the only finding, the chance of developing lupus later is very low according to MedlinePlus.
↑ What a high value means
A positive result means that antinuclear antibodies were detected. This can be linked to systemic lupus erythematosus, other autoimmune diseases such as Sjögren's syndrome, scleroderma, autoimmune hepatitis or thyroid disease, viral infections (then usually temporary), certain medicines or other conditions. Many healthy adults have a positive ANA, especially women over 65; levels rise with age. Further antibody tests usually follow. The assessment belongs with your doctor, often with rheumatology expertise.
When to test
When symptoms could point to an autoimmune disease, such as unexplained fever, rash, fatigue, joint pain and swelling or muscle pain. No special preparation is needed. Some medicines, including birth control pills, procainamide and thiazide diuretics, can affect the result; tell your practice, but do not stop anything on your own.
Frequently asked questions
Does a positive ANA test mean an autoimmune disease? +
Not necessarily. Antinuclear antibodies also occur in many healthy people, more often with age and especially in women over 65. Viral infections and some medicines can trigger them too. Only together with symptoms, further antibody tests and a medical examination does a clear picture emerge.
What do titer and pattern mean? +
The titer indicates how far the blood sample can be diluted before the antibodies are no longer detectable, for example 1:80 or 1:320. The higher the second number, the more antibodies. The pattern describes how the antibodies bind in the cell nucleus, for example homogeneous, speckled or centromere.
What happens after a positive result? +
Usually tests for specific antibodies follow (ANA panel), which help narrow down certain conditions. A diagnosis such as lupus additionally requires matching clinical features.
Does a negative ANA test rule out an autoimmune disease? +
Not completely. A negative result makes an autoimmune disease less likely but does not rule it out with certainty. If symptoms persist, discuss the next steps with your doctor.
Antinuclear antibodies (ANA)
Sources
Last updated: October 05, 2026
This information is for orientation only and does not replace medical advice. Reference ranges can vary by laboratory, method and country.