I have wondered that myself but because we lost our health insurance when we moved to NY, I don't get regular screenings for anything. I had all the tests...they came back negative and I was dx'd with fibro. Other than the usual blood work that they do in a physical, I haven't had a sed rate, RA factor or ANA done in fifteen years. They are about $1000 a piece. I just chalk every new symptom to fibro and figure that when my Rheumy looks me over and doesn't see any obvious signs of something else (like red, swollen joints, weak reflexes or abnormal co-ordination etc) I'll just blame good ole fibro. I've never been tested for Lyme, and probably never will be. Whatever...is all I keep saying!