I'm guessing that physician preference on labs could depend partly on the extent of disease in individual patients. In my case, I have "limited" or "non-severe" WG involving only my ears/nose/sinuses. I'm just happy to be giving away less blood to the lab techs for a while. Regarding PR3 and ANCA, I see that some people have this checked regularly. I have not had it checked since diagnosis. The bit of research I've done suggests that some docs think it's important and can be predictive or diagnostic of flares, at least in some patients... but there are also studies that say it is not of much value after diagnosis. Also related to lab issues, my first rheumatologist had me getting the high sensitivity version of the CRP test. Someone pointed out to me that this is 10x too sensitive to have any meaning for WG monitoring. I finally challenged my current doc on this and she concurred and changed me to the regular CRP test.