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Arthritis and Rheumatism

ANA titer

09/25/2007

Question:

My daughter is 17. When she had mono in July of 2007 her ANA titer was 1600. Now she had her blood work done again and her ANA titer is 2650. Can you tell me what does this mean? All of her other blood tests came back normal. We are going to see a rheumatoid arthritis doctor.

Answer:

An elevated ANA blood by itself is not specific enough to make a diagnosis. ANA elevations may be normal for a given individual (typically low titer, equal to or less than 1:160), reactive to infections (including "mono"), or associated with various diseases including Systemic Lupus Erythematosus, Sjogren's Syndrome, Scleroderma, polymyositis, thyroid disease, inflammatory bowel disease, psoriasis, or others. When you visit with the Rheumatologist, they will ask further questions in an attempt to rule in or rule out rheumatic conditions that can be associated with an elevated ANA. Not all ANA elevations are due to rheumatic diseases.

The values you listed for your daughter's ANA levels may not be accurate. The classic reporting of ANA values titers: 1:10, 1:20, 1:40, 1:80, 1:160, 1:320, and so forth (the second number doubles with each titration). The higher the second number, the greater the positivity. In the titer reporting system, 1600 and 2650 do not exist. Perhaps you meant 1:160 and 1:2560?

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Response by:

Raymond  Hong, MD, MBA, FACR Raymond Hong, MD, MBA, FACR
Formerly, Assistant Professor of Medicine
School of Medicine
Case Western Reserve University