|
Laboratory values
|
RA
|
IRD (n = 56)
|
HI (n = 51)
|
Sensitivity (n = 50)
|
Specificity
|
PPV
|
NPV
|
AUC (ROC) (95%) CI
|
|---|
|
RF IgM (%)
|
43
|
3 (6)
|
4 (8)
|
77
|
93
|
86
|
88
|
0.85 (0.79 to 0.91)
|
|
RF IgA (%)
|
47
|
8 (16)
|
0 (0)
|
84
|
92
|
85
|
91
|
0.88 (0.82 to 0.94)
|
|
Anti-CCP2 (%)
|
46
|
1 (2)
|
1 (2)
|
82
|
98
|
96
|
91
|
0.90 (0.85 to 0.96)
|
|
Anti-CCP3 (%)
|
43
|
4 (8)
|
1 (2)
|
77
|
95
|
90
|
88
|
0.86 (0.80 to 0.92)
|
|
SE 1 or 2 copies (%)
|
17
|
7 (14)
|
5 (10)
|
30
|
88
|
59
|
70
|
0.59 (0.52 to 0.66)
|
|
- SE 1 copy (%)
|
15
|
7 (14)
|
5 (10)
|
27
|
88
|
56
|
68
|
0.57 (0.51 to 0.64)
|
|
- SE 2 copies (%)
|
2
|
0 (0)
|
0 (0)
|
4
|
100
|
100
|
65
|
0.52 (0.49 to 0.54)
|
- Anti-CCP, anti-cyclic citrullinated peptides; AUC, area under the curve in the ROC analysis; HI, healthy individuals; IRD, inflammatory rheumatic diseases; RA, rheumatoid arthritis; RF, rheumatoid factor; Sensitivity, the percentage of RA patients who would be identified as having RA by the laboratory tests (positive test results); Specificity, the percentage of control patients (IRD and HI together) who would be identified as not having RA by the laboratory tests (negative test results); PPV, positive predictive value or the proportion of RA patients with positive test results who are correctly diagnosed as having RA; NPV, negative predictive value or the proportion of control patients with negative test results who are correctly diagnosed as not having RA; SE, shared epitope
