Systemic Lupus Erythematosus (SLE) is characterized by high ANA readings. Otheer auto-immune diseases such as Sjogren syndrome, scleroderma, or mixed connective tissue disease also may have a high ANA. But it can be elevated due to some drugs or infections.
It is usually measured by the dilution needed before there is no reaction, but the lab might not keep trying if there is still a reaction at 1:1000 dilution.
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