Table 1 Receiver Operating Characteristic (ROC) Area under the Curve (AUC) estimates, cut-off estimates to define a positive test, and diagnostic accuracy of positive tests for ESR, CRP and Platelets for a diagnosis of GCA. Numbers in brackets represent 95% confidence intervals
From: The utility of ESR, CRP and platelets in the diagnosis of GCA
ESR (mm/hr) | CRP (mg/L) | Platelets (109/L) | |
|---|---|---|---|
AUC | 0.65 (0.57, 0.72) | 0.72 (0.65, 0.79) | 0.72 (0.65, 0.79) |
Estimated cut-offa | |||
Bx- GCA vs non-GCA | 44 (21, 66) | 23 (12, 35) | 319 (291, 347) |
Bx + GCA vs non-GCA | 47 (28, 65) | 23 (16, 32) | 297 (263, 330) |
All GCA vs non-GCA | 47 (28–65) | 23 (19, 28) | 297 (272, 321) |
Selected cut-off | 50 | 20 | 300 |
Proportion positive at cut-off (%) | |||
non-GCA (n = 131) | 56 (43%) | 42 (32%) | 49 (37%) |
GCA (n = 139) | 91 (65%) | 93 (67%) | 99 (71%) |
All (n = 270) | 147 (54%) | 135 (50%) | 148 (55%) |
Diagnostic accuracy of positive tests | |||
Sensitivity (%) | 65.5 (56.9, 73.3) | 66.9 (58.4, 74.6) | 71.2 (62.9, 78.6) |
Specificity (%) | 57.3 (48.3, 65.9) | 67.9 (59.2, 75.8) | 62.6 (53.7, 70.9) |
Positive Predictive Value (%) | 61.9 (53.5. 69.8) | 68.9 (60.4, 76.6) | 66.9 (58.7, 74.4) |
Negative Predictive Value (%) | 61.0 (51.8, 69.6) | 65.9 (57.3, 73.9) | 67.2 (58.1, 75.4) |
Correct (%) | 61.4 | 67.4 | 67.0 |