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 MPO-ANCA
| Test | Controls (n = 50) | MPA (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; MPA, microscopic polyangiitis; MPO-ANCA, antineutrophil cytoplasmic antibodies to myeloperoxidase. | ||||||||||||
| IFT | 2 | 2 | 0 (0%) | 13 | 13 | 0 (0%) | ||||||
| IHELI | 0 | 0 | 0 (0%) | 9 | 9 | 0 (0%) | ||||||
| A | 0 | 3 | 3 (6%) | 4 | 10 | 6 (14.0%) | ||||||
| B | 1 | 4 | 3 (6%) | 10 | 12 | 2 (13.3%) | ||||||
| E | 0 | 8 | 8 (16%) | 9 | 11 | 2 (13.3%) | ||||||
| F | 0 | 3 | 3 (6%) | 8 | 13 | 5 (33.3%) | ||||||
| G | 0 | 5 | 5 (10%) | 7 | 12 | 5 (33.3%) | ||||||
| H | 0 | 1 | 1 (2%) | 10 | 12 | 2 (13.3%) | ||||||
| I | 0 | 1 | 1 (2%) | 7 | 12 | 5 (33.3%) | ||||||
| J | 0 | 2 | 2 (4%) | 8 | 10 | 2 (13.3%) | ||||||
| K | 0 | 4 | 4 (8%) | 7 | 14 | 7 (46.7%) | ||||||
| L | 0 | 0 | 0 (0%) | 9 | 11 | 2 (13.3%) | ||||||
| M | 0 | 1 | 1 (2%) | 8 | 12 | 4 (26.6%) | ||||||