ANA's are not specific to Lupus, but most people with active Lupus do have elevated ANA. You and your doctor should be aware of the fact that your Lupus could be very active and your ANA levels could be normal. I can understand the desire to monitor ANA levels to determine Lupus activity, and it is probably a pretty good practice. However, if you are displaying signs and symptoms of a flare up and your ANA is normal, please do not let them stop there and try to tell you that your symptoms are not due to Lupus. If the ANA is normal with symptomology, there are other tests that should be run (and one is the ESR).
I wish you the very best
Peace and Blessings
Look For The Good and Praise It!