There is no diagnostic criteria. There is a nomenclature system(naming system) , the revised chapel hill consensus conference nomenclature system 2012. There have been classification criteria proposed by ACR in 2012. There have been draft criteria of GPA/MPA/EGPA and TAK/GCA. These have not yet been approved by the ACR/EULAR. Though these are the result of the ACR/ EULAR led DCVAS study as suggested above. The EULAR/EDTA recommendations can be referred for treatment of AAV. There are Canvasc (Canandian vasculitis research network ) recommendations for treatment of AAV also. I believe there was a call for ACR guidelines for AAV which should come in next few years.