Table 2

Study of ANCA titre cut-off values for the diagnosis of AAV

NSensitivity
(95% CI)		Specificity
(95% CI)		Positive predictive value
(95% CI)		Negative predictive value
(95% CI)		Accuracy
(95% CI)		AUC
(95% CI)
All patients with ANCA titres of ≥65 U/mL2880.94
(0.83 to 0.99)		0.73
(0.67 to 0.78)		0.41
(0.36 to 0.46)		0.98
(0.95 to 1.00)		0.76
(0.71 to 0.81)		0.89
(0.85 to 0.93)
PR3-ANCA-positive patients with ANCA titres ≥106 U/mL1610.86
(0.57 to 0.98)		0.86
(0.79 to 0.91)		0.36
(0.27 to 0.47)		0.98
(0.96:−1.00)		0.86
(0.79 to 0.91)		0.92
(0.86 to 0.98)
MPO-ANCA-positive patients with ANCA titres ≥65 U/mL1270.94
(0.80 to 0.99)		0.69
(0.58 to 0.78)		0.52
(0.45 to 0.60)		0.97
(0.89 to 1.00)		0.76
(0.67 to 0.83)		0.86
(0.79 to 0.92)

  • ANCA, antineutrophil cytoplasmic antibody; AUC, area under the ROC curve; MPO, myeloperoxidase; N, number of subjects; PR3, proteinase 3.