Activity stages of ANCA-associated vasculitides (AAV).
| Activity stage | Definition |
| Localized stage | Upper and/or lower respiratory tract without systemic manifestation, without B symptoms, not organ-threatening1 |
| Early systemic stage | All organ involvement possible, not life-threatening or organ-threatening2 |
| Generalization stage | Renal involvement (kidney involvement) or other organ-threatening manifestation, creatinine < 500 µmol/l (5.6 mg/dl)3 |
| Severe, vital-threatening generalization stage. | Renal involvement or other organ failure, creatinine > 500 µmol/l (5.6 mg/dl)3 |
| Refractory stage | Progressive disease, refractory to standard therapy. |
Legend
- 1ANCA often negative
- 2ANCA negative or positive
- 3ANCA almost always positive
B symptomatology
- Unexplained, persistent or recurrent fever (> 38 °C).
- Night sweats (wet hair, soaked sleepwear).
- Unwanted weight loss (> 10% percent of body weight within 6 months).
