Table 16 Comprehensive external validation performance metrics.
Dataset | Sample size | Overall accuracy (95% CI) | Sensitivity (95% CI) | Specificity (95% CI) | PPV (95% CI) | NPV (95% CI) | AUC (95% CI) | Class imbalance ratio | Imaging quality (mean ± SD) | t-statistic | p-value |
|---|---|---|---|---|---|---|---|---|---|---|---|
Original test | 3750 | 97.3% (96.8–97.8) | 96.8% (96.2–97.4) | 97.7% (97.2–98.2) | 96.2% (95.5–96.9) | 98.1% (97.7–98.5) | 0.993 (0.989–0.997) | 1:1.8 (balanced) | 4.7 ± 0.3 | – | – |
ExtVal-1 (rural) | 12,400 | 89.4% (88.7–90.1) | 87.2% (86.3–88.1) | 91.1% (90.4–91.8) | 84.7% (83.6–85.8) | 92.8% (92.2–93.4) | 0.947 (0.941–0.953) | 1:47.3 (severe) | 2.9 ± 0.8 | -12.34 | < 0.001 |
ExtVal-2 (urban) | 18,600 | 91.7% (91.2–92.2) | 89.8% (89.1–90.5) | 93.2% (92.7–93.7) | 88.4% (87.6–89.2) | 94.1% (93.7–94.5) | 0.964 (0.960–0.968) | 1:18.6 (high) | 3.4 ± 0.6 | -9.87 | < 0.001 |
ExtVal-3 (mobile) | 9800 | 86.2% (85.3–87.1) | 83.9% (82.8–85.0) | 88.1% (87.2–89.0) | 81.3% (80.1–82.5) | 89.7% (88.9–90.5) | 0.921 (0.914–0.928) | 1:62.1 (extreme) | 2.1 ± 0.9 | -15.67 | < 0.001 |
ExtVal-4 (international) | 14,200 | 88.9% (88.3–89.5) | 86.7% (85.9–87.5) | 90.8% (90.2–91.4) | 85.2% (84.3–86.1) | 91.4% (90.9–91.9) | 0.951 (0.946–0.956) | 1:23.4 (high) | 3.2 ± 0.7 | -11.42 | < 0.001 |
ExtVal-5 (early pathology) | 7300 | 84.6% (83.6–85.6) | 81.2% (79.9–82.5) | 87.3% (86.2–88.4) | 78.9% (77.4–80.4) | 88.8% (87.8–89.8) | 0.912 (0.904–0.920) | 1:156.7 (extreme) | 4.1 ± 0.5 | -18.23 | < 0.001 |
ExtVal-6 (emergency) | 11,100 | 82.3% (81.5–83.1) | 79.8% (78.7–80.9) | 84.2% (83.3–85.1) | 76.4% (75.2–77.6) | 86.1% (85.3–86.9) | 0.895 (0.887–0.903) | 1:34.2 (severe) | 2.3 ± 1.1 | -19.84 | < 0.001 |
ExtVal-7 (longitudinal) | 8900 | 90.8% (90.1–91.5) | 88.4% (87.5–89.3) | 92.7% (92.0-93.4) | 87.1% (86.1–88.1) | 93.2% (92.6–93.8) | 0.958 (0.952–0.964) | 1:15.2 (moderate) | 3.8 ± 0.4 | -8.76 | < 0.001 |
External average | 82,300 | 87.7% (87.4–88.0) | 85.3% (84.9–85.7) | 89.6% (89.3–89.9) | 83.1% (82.6–83.6) | 90.9% (90.6–91.2) | 0.935 (0.932–0.938) | 1:39.6 | 3.1 ± 0.7 | -13.45 | < 0.001 |