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Table 2 Serological and immunogenetic characteristics in RA patients, controls with inflammatory rheumatic diseases, and healthy individuals

From: Diagnostic value of anti-cyclic citrullinated peptides and association with HLA-DRB1 shared epitope alleles in African rheumatoid arthritis patients

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)
  1. 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