Odds ratios of obtaining a positive temporal artery biopsy (TAB) as a function of the sample length (derived from 1520 TAB datasets)
| TAB length | Diagnostic sensitivity | |||
|---|---|---|---|---|
| All giant cell arteritis | Giant cell arteritis with giant cells | |||
| n/total n (%) | OR (95% CI) | n/total n (%) | OR (95% CI) | |
| *Reference value. | ||||
| †p = 0.016; ‡p = 0.055. | ||||
| CI, confidence interval; OR, odds ratio. | ||||
| Class | ||||
| <0.5 cm* | 2/66 (3.0%) | 1 | 2/66 (3.0%) | 1 |
| 0.5–0.9 cm | 56/381 (14.7%) | 5.5 (1.3 to 23.2) | 38/381 (10.0%) | 3.5 (0.8 to 15.1) |
| 1.0–1.4 cm | 79/486 (16.3%) | 6.2 (1.5 to 25.9) | 61/486 (12.6%) | 4.6 (1.1 to 19.2) |
| 1.5–1.9 cm | 45/290 (15.5%) | 5.9 (1.4 to 24.9) | 33/290 (11.4%) | 4.1 (0.96 to 17.6) |
| 2.0–2.4 cm | 23/172 (13.4%) | 4.9 (1.1 to 21.6) | 19/172 (11.0%) | 4.0 (0.9 to 17.6) |
| ⩾2.5 cm | 18/125 (14.4%) | 5.4 (1.2 to 24.0) | 11/125 (8.8%) | 3.1 (0.7 to 14.4) |
| Change point | ||||
| <0.5 cm* | 2/66 (3.0%) | 1 | 2/66 (3.0%) | 1 |
| ⩾0.5 cm | 220/1454 (15.1%) | 5.7 (1.4 to 23.6%)† | 162/1454 (11.1%) | 4.0 (0.97 to 16.5*)‡ |