Explanation on ANA....

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ANA (Antinuclear Antibodies) Test

Test Overview

An antinuclear antibody (ANA) test measures the amount and pattern of antibodies in your blood that work against your own body (autoimmune).The body's immune system normally attacks and destroys foreign substances such as bacteria and viruses. However, in disorders known as autoimmune diseases, the immune system attacks and destroys the body's normal tissues. When a person has an autoimmune disease, the immune system produces antibodies that attach to the body's own cells as though they were foreign substances, often causing them to be damaged or destroyed. Rheumatoid arthritis and systemic lupus erythematosus are examples of autoimmune diseases.An ANA test is used along with your symptoms, physical examination, and other tests to find an autoimmune disease.

Why It Is Done

An antinuclear antibodies (ANA) test is done to help identify problems with the immune system, such as:

Rheumatoid arthritis.

Systemic lupus erythematosus (SLE).

Polymyositis.

Scleroderma.

Sjögren's syndrome.

Results

An antinuclear antibody (ANA) test measures the amount and pattern of antibodies in your blood that work against your own body (autoimmune).The results of an ANA test are usually given in titers. A titer is a measure of how much the blood sample can be diluted before the presence of the antibodies can no longer be detected.For example, a titer of 1 to 40 (1:40) means that antibodies can be detected when 1 part of the blood sample is diluted by up to 40 parts of a salt solution (saline). A larger second number means there are more antibodies in the blood. Therefore, a titer of 1 to 80 indicates more antibodies in the blood than a titer of 1 to 40.There are different subtypes of ANA which may have a range of normal values.NormalNormal values may vary from lab to lab. Results will usually be available in about 1 week.Antinuclear antibodiesNormal titer1:40 or less

High valuesA high ANA titer may be caused by:

Autoimmune connective tissue diseases. Examples include:

Rheumatoid arthritis. More than one-third of people with rheumatoid arthritis have a high ANA titer.

Systemic lupus erythematosus (SLE). Almost all people with SLE have a high ANA titer. However, most people with a high ANA titer do not have SLE.

Scleroderma.

Sjögren's syndrome.

Juvenile rheumatoid arthritis.

Polymyositis.

Raynaud's syndrome.

Autoimmune diseases of other organs. Examples include:

's disease.

Diseases of the blood cells, such as vitamin B12 deficiency, idiopathic thrombocytopenia (ITP), and hemolytic anemia.

Liver disease, such as hepatitis.

Thyroid disease, such as Hashimoto's thyroiditis.

Medicines, such as those used to treat high blood pressure, heart disease, and tuberculosis (TB).

Viral infections.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

Taking medicine. Many medicines can change the results of this test. Be sure to tell your doctor about all the nonprescription and prescription medicines you take.

Aging. Some older adults (5% to 40%) may have mildly elevated levels. Older women appear to have higher ANA titers than older men.

What To Think About

Autoimmune diseases cannot be diagnosed by the results of the ANA test alone. A complete medical history, physical examination, and the results are other tests are used with the ANA test to help identify autoimmune diseases, such as systemic lupus erythematosus (SLE) or rheumatoid arthritis.

Some healthy people can have an increased ANA titer. For instance, some people with a family history of autoimmune disease may have a high ANA titer. The higher the titer, however, the more likely it is that the person has an autoimmune disease.

ANA levels can increase as a person ages.

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