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ANA (Antinuclear Antibodies)

In certain conditions the immune system attacks part of its own cells, the nuclei, by producing antinuclear antibodies. Alone, these antibodies are harmless as they cannot penetrate living cells. But, in some cases they form tissue damaging antigen-antibody complexes.

Almost all people with Systemic lupus erythematosus (Lupus) develop these antibodies, a negative test result essentially rules out a lupus diagnosis. However, a positive result does not always mean lupus. Rheumatoid arthritis. Sjogrens syndrome, liver disease, scleroderma and other conditions may be associated with an elevated ANA.

Type of Test: Blood Test

What the Results Mean:

The results are expressed in a titer. A value is considered normal if it less than 1:20.

A low positive result may indicate other conditions. The higher the result, the more likely it is that that person has lupus.

Besides the concentration of antibodies, patterns of antibodies can be indentified that indicate certain diseases.

References:
Mosby's Manual of Diagnostic and Laboratory Tests by Kathleen Deska Pagana, Timothy James Pagana.
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