A rheumatologist should be diagnosing Systemic Lupus (SLE) based on having 4 of 11 symptoms, as described by
www.lupus.org. As Tinkerbell mentioned, diagnosis of Cutaneous (CLE) and Discoid (DLE) Lupus is slightly different, it could be done by a dermo via biopsy. Another kind of Lupus is Lupus Nephritis, which primarily attacks the kidneys.
I assume you mean you were NOT diagnosed because of a non-positive ANA. If you are talking about
Systemic Lupus, your rheumatologist should be using the 4 of 11 guideline - you CAN have Lupus without having a positive ANA.
Yes, plenty of people are NOT diagnosed because they do NOT have a positive ANA.
If that were the case for me, and I felt strongly that I met several of the other 11 symptoms, I would probably want a second opinion from another rheumatologist.