Table 4: Positive predictive values (PPV) of ANCA testing for AAV.

Immunological markerAll patients PPV% (95%CI)Inpatients PPV% (95%CI)Outpatients PPV% (95%CI)

p-ANCA13.0 (9.5–16.6)14.6 (9.8–19.4)17.8 (11.5–24.2)
c-ANCA67.9 (55.6–80.1)57.9 (42.2–73.6)88.8 (74.4–100)
p-ANCA plus c-ANCA20.6 (16.7–24.6)21.3 (16.2–26.4)25.9 (19.1–32.8)
Anti-MPO71.7 (61.8–81.8)67.4 (53.8–80.9)78.1 (63.8–92.4)
Anti-PR376.9 (66.7–87.2)69.4 (54.4–84.5)86.2 (73.7–98.8)
Anti-MPO plus anti-PR374.1 (66.9–81.3)68.3 (58.2–78.4)81.9 (72.3–91.6)
p-ANCA/MPO80.3 (70.4–90.3)77.7 (64.2–91.4)84.0 (69.6–98.4)
c-ANCA/PR390.5 (81.6–99.4)84.6 (70.7–98.5)100
p-ANCA/MPO plus c-ANCA/PR384.5 (77.5–91.5)80.6 (70.8–90.5)90.2 (81.2–99.3)