Table 4.

Sensitivity, specificity, and likelihood ratios for persistent arthritis for different minimum cut-off levels for anti-CCP2 and IgM RF

Cut-off anti-CCP2 (units/ml)	Sensitivity	Specificity	Accuracy	LR+ (95% CI)	LR- (95% CI)
2	0.71	0.55	0.63	1.59 (1.32 to 1.91)	0.53 (0.41 to 0.69)
3	0.58	0.72	0.65	2.06 (1.60 to 2.65)	0.58 (0.48 to 0.71)
4	0.47	0.80	0.65	2.38 (1.73 to 3.27)	0.66 (0.56 to 0.77)
5	0.43	0.87	0.67	3.23 (2.18 to 4.77)	0.66 (0.57 to 0.77)
10	0.35	0.93	0.66	4.98 (2.88 to 8.58)	0.71 (0.69 to 1.79)
15	0.32	0.95	0.66	5.91 (3.20 to 10.92)	0.72 (0.64 to 0.80)
20	0.31	0.95	0.65	5.59 (3.02 to 10.37)	0.74 (0.66 to 0.82)
25	0.30	0.95	0.64	6.04 (3.17 to 11.51)	0.74 (0.67 to 0.82)
Cut-off IgM RF (units/ml)	Sensitivity	Specificity	Accuracy	LR+	LR-
2	0.71	0.41	0.55	1.20 (1.04 to 1.39)	0.71 (0.53 to 0.94)
3	0.62	0.54	0.58	1.34 (1.13 to 1.65)	0.70 (0.55 to 0.88)
5	0.51	0.69	0.61	1.67 (1.30 to 2.15)	0.71 (0.59 to 0.84)
7	0.43	0.77	0.61	1.85 (1.37 to 2.51)	0.74 (0.64 to 0.86)
10	0.33	0.87	0.62	2.49 (1.66 to 3.76)	0.77 (0.68 to 0.87)
15	0.31	0.92	0.64	3.69 (2.22 to 6.12)	0.75 (0.68 to 0.84)
20	0.29	0.95	0.64	5.28 (2.84 to 9.81)	0.75 (0.68 to 0.83)
25	0.28	0.95	0.64	5.69 (2.97 to 10.89)	0.76 (0.69 to 0.83)

CI: confidence interval; LR+: positive likelihood ratio; LR-: negative likelihood ratio.