Diagnostic performance of antiphospholipid antibodies for secondary APS in SLE
| Sensitivity (%) | Specificity (%) | PLR | NLR | PPV (%) | NPV (%) | Accuracy (%) | Youden’s index | OR (95% CI) | |
| LAC | 96.00 | 79.38 | 4.66 | 0.05 | 54.55 | 98.72 | 82.79 | 0.75 | 92.40 (21.53 to 396.54) |
| Anti-β2GPI-DI IgG | 32.00 | 91.87 | 3.93 | 0.74 | 48.48 | 84.96 | 80.31 | 0.24 | 5.31 (2.45 to 11.52) |
| Anti-β2GPI IgG/M | 56.00 | 78.71 | 2.63 | 0.56 | 39.44 | 87.85 | 74.21 | 0.35 | 4.71 (2.45 to 9.03) |
| aCL IgG/M | 62.00 | 81.95 | 3.44 | 0.46 | 45.59 | 89.84 | 78.04 | 0.44 | 7.41 (3.78 to 14.52) |
| Single aPL positive | 34.00 | 82.78 | 1.97 | 0.80 | 32.08 | 83.98 | 73.36 | 0.17 | 2.48 (1.25 to 4.92) |
| Isolated LAC | 30.00 | 91.87 | 3.69 | 0.76 | 46.88 | 84.58 | 79.92 | 0.22 | 4.84 (2.21 to 10.58) |
| Isolated anti-β2GPI IgG/M | 2.00 | 94.26 | 0.35 | 1.04 | 7.69 | 80.08 | 76.45 | 0.04 | 0.34 (0.04 to 2.64) |
| Isolated aCL IgG/M | 2.00 | 96.65 | 0.60 | 1.01 | 12.50 | 80.48 | 78.38 | 0.01 | 0.59 (0.07 to 4.90) |
| Double aPL positivity (n (%)) | 18.00 | 93.78 | 2.89 | 0.87 | 40.91 | 82.70 | 79.15 | 0.12 | 3.31 (1.33 to 8.26) |
| LAC−, anti-β2GPI IgG/M+, aCL IgG/M+ | 0.00 | 95.69 | 0.00 | 1.04 | 0 | 80.00 | 77.22 | NA | 0.21 (0.01 to 3.65) |
| LAC+, anti-β2GPI IgG/M−, aCL IgG/M+ | 12.00 | 99.52 | 25.08 | 0.88 | 85.71 | 82.54 | 82.63 | 0.12 | 28.36 (3.33 to 241.53) |
| LAC+, anti-β2GPI IgG/M+, aCL IgG/M− | 6.00 | 98.56 | 4.18 | 0.95 | 50.00 | 81.42 | 80.69 | 0.05 | 4.38 (0.86 to 22.40) |
| Triple aPL positive | 48.00 | 90.91 | 5.28 | 0.57 | 55.81 | 87.96 | 82.63 | 0.39 | 9.23 (4.46 to 19.12) |
aCL, anticardiolipin; Anti-β2GPI-DI, anti-β2GPI-domain I; aPL, antiphospholipid antibody; LAC, lupus anticoagulant; NA, not available; NLR, negative likelihood ratio; NPV, negative predictive value; PLR, positive likelihood ratio; PPV, positive predictive value.