Most patients with lupus have a positive ANA test, but most patients with a positive ANA test do not have lupus. The ANA is a starting point - if it's positive, the doctor will then be interested in knowing how high the level is (titer) and what the staining pattern is of the cells on the slide. From there, there is a myriad of other tests that they run, but they typically begin with the ANA. But, like I said, there is a small percentage of people with lupus who may not test ANA positive for some reason. If it's been a while since you last had one done, it might be a good idea to be retested, especially if you're still getting that butterfly rash. I wouldn't waste any more time with your gp - if you can, I'd try again for that rheumatology referral. I'm sorry you've had to go through all this.

And I'm not sure whether or not lupus is a diagnosis of exclusion per se, but it is very difficult to diagnose and there aren't many tests that are very specific for it. It's like, "if test A is positive, then there's a 30% chance...if test B is positive, there's a 25% chance", etc, etc. But if you've got tests A, B, D and Q positive...well then you may be on to something.