Table 2.

Performance of the four biomarkers based on ACR-modified criteria.

Variable	sCal EIA, µg/ml	sCal CLIA, µg/ml	ESR, mm/h		CRP, mg/L
AUC (95% CI)	0.64 (0.42–0.82)	0.58 (0.38–0.78)	0.73 (0.50–0.87)		0.75 (0.54–0.90)
Cut-off for maximum efficiency	5.3	2.0	20	18	3.1
Sensitivity	33.3%	75%	41.7%	50%	66.7%
Specificity	100%	53.8%	100%	92.3%	92.3%
LR+	–	1.62	–	6.50	8.66
LR-	0.66	0.46	0.58	0.54	2.77
Cut-off based on ROC	2.9	2.0	10		3.1
Sensitivity	75%	75%	66.7%		66.7%
Specificity	53.8%	53.8%	69.2%		92.3%
LR+	1.62	1.62	2.16		8.66
LR-	0.46	0.46	0.48		0.36

AUC, area under the curve; ROC, receiver operating characteristic; LR+, positive likelihood ratio; LR-, negative likelihood ratio; sCal, serum calprotectin; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; CI, confidence interval.