For GPA, PR3-ANCA has 66% sensitivity and MPO-ANCA has 24% sensitivity; for MPA, PR3-ANCA has 26% sensitivity and MPO-ANCA has 50–80% sensitivity; and for EGPA, PR3-ANCA has 2–3% sensitivity and MPO- ANCA has 30–40% sensitivity [25]. The gene discussed is MPO; the disease is granulomatosis with polyangiitis.