Antinuclear Antibodies

The Basics

Written by the doctors and editors at UpToDate пїЅ пїЅ

What are antinuclear antibodies? " пїЅ Antinuclear antibodies, called "ANA " пїЅ for short, are proteins in the blood. They are made by the bodys infection-fighting system, which is also called the immune system. пїЅ пїЅ

Normally, a person's immune system makes antibodies when he or she gets an infection. The antibodies attack the germs causing the infection. пїЅ пїЅ

If a person's immune system isn't working normally, it sometimes makes antibodies that attack his or her own body. This is called an autoimmune disease. Antibodies that attack a person's own body are also called autoantibodies. ANA are specific autoantibodies that attack substances inside of cells. пїЅ пїЅ

Autoantibodies can damage different parts of the body, including the blood, skin, joints, kidneys, lungs, and nervous system. пїЅ пїЅ

What is an ANA test? " пїЅ An ANA test is a blood test that measures the amount of ANA in your blood. пїЅ пїЅ

A "negative " пїЅ result means that you have no (or very little) ANA in your blood. пїЅ пїЅ

A "positive " пїЅ result means that you have ANA in your blood. пїЅ пїЅ

Why might a doctor or nurse order an ANA test? " пїЅ A doctor or nurse will order an ANA test to help figure out if you have an autoimmune disease. Many types of autoimmune diseases can cause a positive ANA test result. Some autoimmune diseases affect the whole body. These include: пїЅ пїЅ

Lupus
Scleroderma
Mixed connective tissue disease
Polymyositis
Dermatomyositis
Rheumatoid arthritis

Other autoimmune diseases affect only one part of the body, such as the thyroid (a gland in the neck), liver, or lungs. пїЅ пїЅ

What does a negative ANA test result mean? " пїЅ If you have a negative result, you probably do NOT have an autoimmune disease. пїЅ пїЅ

What does a positive ANA test result mean? " пїЅ If you have a positive result, you might have an autoimmune disease. пїЅ пїЅ

It's important to know that a positive result does not always mean a person has an autoimmune disease. Some people with a positive ANA result do not have an autoimmune disease and never get one. The higher the number (called the "titer " пїЅ) of your ANA test, the greater the chance that you have an autoimmune disease. пїЅ пїЅ

Also, some people with a positive ANA result do not have an autoimmune disease, but have an infection instead. пїЅ пїЅ

To figure out whether you have an autoimmune disease, your doctor will also learn about your symptoms, do an exam, and order other lab tests. He or she might order blood tests that look for more specific autoantibodies. These can help your doctor figure out which type of autoimmune disease you might have. пїЅ пїЅ

All topics are updated as new evidence becomes available and our peer review process is complete. пїЅ пїЅ

This topic retrieved from UpToDate on: Nov 04, 2014. пїЅ пїЅ

Topic 86734 Version 4.0 пїЅ пїЅ

Release: 22.8 - C22.206 пїЅ пїЅ

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Antinuclear Antibodies

The Basics

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