Assuming lab accuracy, what are some of the hallmarks and symptoms that would lead to a diagnosis of ANA-negative lupus as opposed to any other autoimmune condition?  

I would not make an initial diagnosis of ANA-negative systemic lupus erythematosus (SLE) lightly, especially since there are so many mimics of SLE. However, it does occur, even in early, untreated patients. Even some of the best lupus centers in the world (SLICC) have a 6% prevalence of ANA-negative...