Table 2.
Accuracy parameters of radioimmunoassay and enzyme‐linked immunosorbent assay tests
| Category | Tests | Sensitivity (%) | Specificity (%) | PPV (%) | NPV (%) | Diagnostic accuracy (%) | Likelihood ratio of a positive test | Likelihood ratio of a negative test |
|---|---|---|---|---|---|---|---|---|
| All | RIA | 57.0 (45.3–68.1) | 97.5 (91.4–99.7) | 95.7 (85.5–99.5) | 69.4 (59.9–77.8) | 77.2 (69.9–83.5) | 22.5 (5.7–89.6) | 0.4 (0.3–0.6) |
| ELISA | 60.8 (49.1–71.6) | 100.0 (93.2–100.0) | 100.0 (89.1–100.0) | 71.8 (62.4–80.0) | 80.4 (73.3–86.3) | – | 0.4 (0.3–0.5) | |
| Acute type | RIA | 44.9 (30.7–59.8) | 97.5 (91.2–99.7) | 91.7 (73.0–99.0) | 74.0 (64.5–82.1) | 77.3 (69.1–84.3) | 17.7 (4.4–72.1) | 0.6 (0.4–0.7) |
| ELISA | 55.1 (40.2–69.3) | 100.0 (93.2–100.0) | 100.0 (81.7–100.0) | 78.2 (68.9–85.8) | 82.8 (75.1–88.9) | – | 0.4 (0.3–0.6) | |
| Slowly progressive type | RIA | 79.3 (60.3–92.0) | 97.5 (91.2–99.7) | 92.0 (74.0–99.0) | 92.8 (84.9–97.3) | 92.6 (85.9–96.7) | 31.3 (7.9–124.6) | 0.2 (0.1–0.4) |
| ELISA | 69.0 (49.2–84.7) | 100.0 (93.2–100.0) | 100.0 (76.2–100.0) | 89.8 (81.5–95.2) | 91.7 (84.8–96.1) | – | 0.3 (0.2–0.5) |
Data are presented as percent, ratio and number (95% confidence interval). ELISA, enzyme‐linked immunosorbent assay; NPV, negative predictive value; PPV, positive predictive value; RIA, radioimmunoassay.