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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
  1. aCut-off values were determined at the maximum of the product of the sensitivity and specificity (Liu’s method)