Table 1

Overview of the results for proteinase 3 (PR3)-antineutrophil cytoplasmic antibodies (ANCA) and myeloperoxidase (MPO)-ANCA obtained by immunoassays from different commercial sources1–8 and for cytoplasmic pattern ANCA (C-ANCA) and perinuclear pattern ANCA (P-ANCA) by indirect immunofluorescence (IIF) performed at two sites (Copenhagen (9) and Bad Bramstedt (10))

	Enzyme immunoassay										IIF
	PR3	MPO	1	2	3	4	5	6	7	8		9	10
Controls n=924	Neg	Neg	904	893	895	883	906	897	894	872	Neg	725	866
	Pos	Neg	7	13	10	10	6	6	7	17	C-ANCA	27	19
	Neg	Pos	10	15	16	28	11	19	19	33	P-ANCA	172	34
	Pos	Pos	3	3	3	3	1	2	4	2	C-ANCA+P-ANCA	0	0
											A-ANCA		5
GPA n=186	Neg	Neg	22	21	26	20	28	23	21	25	Neg	39	22
	Pos	Neg	148	146	140	144	140	143	145	140	C-ANCA	119	144
	Neg	Pos	16	15	19	22	18	19	20	18	P-ANCA	27	20
	Pos	Pos	0	4	1	0	0	1	0	4	C-ANCA+P-ANCA	1	0
MPA n=65	Neg	Neg	12	8	8	5	10	9	6	16	Neg	4	6
	Pos	Neg	4	2	3	3	3	3	3	3	C-ANCA	3	4
	Neg	Pos	47	53	54	56	51	52	56	44	P-ANCA	58	55
	Pos	Pos	2	2	0	1	1	1	0	2	C-ANCA+P-ANCA	0	0
Accuracy*			0.954	0.949	0.946	0.944	0.952	0.950	0.951	0.922		0.794	0.927

Cut-off values proposed by the manufacturer were used.
The assays included were from Inova (QuantaLite (1) and QuantaFlash (2)), Thermo-Fisher (EliA) (3), Bio-Rad (BioPlex 2200) (4), Euro-Diagnostica (5), Orgentec (6), Euroimmun (7) and Medipan (CytoBead assay) (8).
*Accuracy was calculated as follows:
A-ANCA, atypical ANCA; GPA, granulomatosis with polyangiitis; MPA, microscopic polyangiitis; MPO, myeloperoxidase; Neg, negative; Pos, positive.