Table 4. Comparison of classical with automated anti-neutrophil cytoplasmic antibody (ANCA) endpoint-titer analysis.

Classical (1/titer)										Automated (1/titer)
	= <10	20	40	80	160	320	640	1280	2560	5120	N
= <10	402 (99.3%)	2 (0.5%)	1 (0.2%)	0	0	0	0	0	0	0	405
20	8 (12.3%)	55 (84.6%)	1 (1.5%)	1 (1.5%)	0	0	0	0	0	0	65
40	0	6 (27.3%)	13 (59.1%)	3 (13.6%)	0	0	0	0	0	0	22
80	0	0	5 (26.3%)	12 (63.2%)	2 (10.5%)	0	0	0	0	0	19
160	0	0	0	4 (33.3%)	6 (50.0%)	1 (8.3%)	0	1 (8.3%)	0	0	12
320	0	0	0	0	6 (24.0%)	12 (48.0%)	7 (28.0%)	0	0	0	25
640	0	0	0	0	2 (8.3%)	6 (25.0%)	11 (45.8%)	5 (20.8%)	0	0	24
1280	0	0	0	0	0	1 (7.7%)	4 (30.8%)	7 (53.8%)	1 (7.7%)	0	13
2560	0	0	0	0	0	0	0	0	1 (50.0%)	1 (50.0%)	2
5120	0	0	0	0	0	0	0	0	2 (40.0%)	3 (60.0%)	5
	410	63	20	20	16	20	22	13	4	4	592

ANCA endpoint titers were determined by serial dilution of the 592 samples included in the study by classical indirect immunofluorescence (IIF) and compared to those detected by automated CytoBead IIF on the digital IIF interpretation system Aklides using a 1 to 20 serum dilution only.