Yellwdaisy,
Just so you know, 20% of people who have rheumatoid arthritis will test negative for the rheumatoid factor, which means that if this test comes back positive, you definitely have the disease, but if it comes back negative, it doesn't necessarily mean that you don't. I've had RA for 26 years (and have the deformed hands, feet, etc. to prove it!) but have never tested positive for the rheumatoid factor.
Also, RA will be bilaterally symmetrical, unliike osteo arthritis--meaning that if you have it in one hand (or knee, or wrist), you will have it in the other, as well.
Best of luck to you in finding out what's going on with you--it can be a challenge!