Table 2.
Diagnostic performances of IgG index, IgG loc, K index and K loc for OB detection by IEF.
| OB Detection | ||||
|---|---|---|---|---|
| IgG Index | IgG loc | K Index | K loc | |
| Sensitivity (%) | 48.0 (41.2–54.9) | 47.6 (40.6–54.7) | 96.5 (93.0–98.3) | 95.8 (91.8–97.8) |
| Specificity (%) | 93.8 (90.3–96.1) | 95.5 (92.0–97.4) | 89.8 (85.7–92.9) | 93.3 (89.4–95.8) |
| Likelihood ratio for a positive test | 7.8 (4.8–12.6) | 10.5 (5.8–19.0) | 9.48 (6.7–13.5) | 14.2 (8.8–22.9) |
| Likelihood ratio for a negative test | 0.6 (0.5–0.6) | 0.6 (0.5–0.6) | 0.04 (0.02–0.08) | 0.04 (0.02–0.09) |
| Positive predictive value (%) | 85.1 (77.4–90.5) | 89.1 (81.5–93.8) | 87.4 (82.5–91.2) | 91.9 (87.2–94.9) |
| Negative predictive value (%) | 71.1 (66.2–75.5) | 70.0 (64.8–74.7) | 97.2 (94.4–98.7) | 96.5 (93.3–98.2) |
| Efficiency (%) | 74.4 (70.3–78.1) | 74.5 (70.2–78.4) | 92.7 (89.9–94.7) | 94.4 (91.8–96.2) |
| Pre-test probability (prevalence) (%) | 42.3 (37.9–46.8) | 43.8 (39.2–48.6) | 42.3 (37.9–48.8) | 44.3 (39.6–49.0) |
| Pre-test odds | 0.7 (0.6–0.9) | 0.8 (0.7–0.9) | 0.7 (0.6–0.9) | 0.8 (0.7–0.96) |
| Post-test odds | 5.7 (2.9–11.1) | 8.2 (3.7–17.9) | 6.9 (4.1–11.9) | 11.3 (5.8–22.0) |
| Post-test probability (%) | 85.1 (74.6–91.7) | 89.1 (78.8–94.7) | 87.4 (80.3–92.2) | 91.9 (85.3–95.7) |
| Number needed to diagnose (NND) | 2.4 (3.2–2.0) | 2.3 (3.2–1.9) | 1.2 (1.3–1.1) | 1.1 (1.2–1.1) |
The analysis was performed for OB (types 2 and 3 by IEF) versus absence of OB (types 1, 4 and 5 by IEF); data are reported with their 95% confidence intervals.