It's been hundreds of years,
@ebethc , since I was tested. At the time (1986) they did ANA (anti-nuclear antibody) tests. I would not expect the same tests to be used today. Anything that would be used to screen for lupus (systemic lupus erythematosus) or rheumatoid arthritis would be a place to start, I would think. If your doctor doesn't want to test (since he may not know what to do with the results) ask if s/he would consider referring you to a rheumatologist - especially if you have joint or muscle pain.
My doctor (1986) sent me home with his text book from medical school (1965) and told me to read Chapter 11 on Diffuse Collagenoses. It was in there, whatever was going on. I was one of the lucky ones: spontaneous remission that started after 4 weeks. It took about 10 years for the sed rate to be normal again, and it was a long road back (about a year after the spontaneous remission started), with physical therapy, yoga, strength training, aerobics, etc. I was literally not strong enough to complete a major shopping trip when I was doing the physical therapy. But the remission held with only one
minor incident about 7 years later.