Comparison of false positive and true positive results applying the provided and optimum cut off points in enzyme linked immunosorbent assay kits for detection of PR3-ANCA
| Test | Controls (n = 50) | WG (n = 15) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| False positive results | Additional false positive results | True positive results | Additional positive results | |||||||||
| Provided cut off | Optimum cut off | Optimum cut off | Provided cut off | Optimum cut off | Optimum cut off | |||||||
| IFT, indirect immunofluorescence technique; IHELI, in-house enzyme linked immunosorbent assay; PR3-ANCA, antineutrophil cytoplasmic antibodies to proteinase 3; WG, Wegener’s granulomatosis. | ||||||||||||
| IFT | 1 | 1 | 0 (0%) | 11 | 11 | 0 (0%) | ||||||
| IHELI | 0 | 0 | 0 (0%) | 10 | 10 | 0 (0%) | ||||||
| A | 0 | 5 | 5 (10%) | 9 | 12 | 3 (20.0%) | ||||||
| B | 0 | 2 | 2 (4%) | 2 | 10 | 8 (53.4%) | ||||||
| E | 0 | 2 | 2 (4%) | 7 | 10 | 3 (20.0%) | ||||||
| F | 1 | 9 | 8 (16%) | 4 | 9 | 5 (33.4%) | ||||||
| G | 0 | 2 | 2 (4%) | 9 | 10 | 1 (6.7%) | ||||||
| H | 1 | 1 | 0 (0%) | 9 | 10 | 1 (6.7%) | ||||||
| I | 0 | 3 | 3 (6%) | 9 | 13 | 4 (20.7%) | ||||||
| J | 0 | 6 | 6 (12%) | 9 | 11 | 2 (13.3%) | ||||||
| K | 0 | 0 | 0 (0%) | 9 | 10 | 1 (6.7%) | ||||||
| L | 0 | 0 | 0 (0%) | 6 | 8 | 2 (13.3%) | ||||||
| M | 2 | 4 | 2 (4%) | 4 | 8 | 4 (26.7%) | ||||||