Health care providers sometimes order an antinuclear antibody (ANA) blood test to check for autoimmune diseases (when the immune system mistakenly works against a person's own body). But a positive ANA test result doesn't always mean that someone has an autoimmune disease. 

Completely healthy people can have a positive ANA test. So can those who:

• have an autoimmune disease
• have certain infections
• take some types of medicines
• have a close relative with an autoimmune disease

The test results alone don't diagnose a health condition. Health care providers look at symptoms, results from other blood tests and medical tests, and the ANA test result to diagnose health conditions.

Follow your health care provider's advice for:

• taking your child for any other blood tests or medical tests
• going to any specialists, such as a rheumatologist (a doctor who treats conditions of the joints, muscles, and bones)
• what symptoms to watch for (this depends on why your health care provider ordered the ANA test)
• when to follow up

Your child gets:

• any of the symptoms that your health care provider told you to watch for
• any new or worse symptoms, such as joint pain, a rash, tiredness, diarrhea, or weight changes

You know your child best. Call your health care provider if your child has any symptoms that worry you.

How will my health care provider know if my child has an autoimmune disease? Depending on your child's symptoms, your health care provider may order more blood tests and other medical tests. These tests look for other, more specific signs of autoimmune diseases. Your health care provider will look at these test results along with your child's symptoms and any other test results to make a diagnosis.