Overview of diagnostic characteristics of all conclusive sonographies
| N total | N conclusive (% of total) | Sensitivity (95% CI) | Specificity (95% CI) | PPV* (95% CI) | NPV* (95% CI) | LR+ (95% CI) | LR− (95% CI) | N inconclusive (% of total) | |
| Overall | 508 | 308 | 89.6 (82.1 to 94.3) | 93.8 (89.1 to 96.6) | 87.98 (80.84 to 92.71) | 94.65 (91.18 to 96.80) | 14.4 (8.3 to 25.01) | 0.11 (0.06 to 0.19) | 200 |
| Radiologists | 166 | 87(52.4) | 90.32 (74.25 to 97.96) | 91.07 (80.38 to 97.04) | 83.72 (68.85 to 92.29) | 94.88 (86.29 to 98.20) | 10.12 (4.35 to 25.54) | 0.11 (0.04 to 0.31) | 79 (47.6) |
| ED physicians overall | 342 | 221(64.6) | 89.29 (80.63 to 94.98) | 94.89 (89.76 to 97.92) | 89.88 (81.13 to 94.83) | 94.57 (90.37 to 97.0) | 17.47 (8.46 to 36.1) | 0.11 (0.06 to 0.21) | 121 (35.4) |
| Advanced ED sonographers | 154† | 117(75.97) | 90.91 (78.33 to 97.47) | 94.52 (86.56 to 98.49) | 89.4 (76.4 to 95.65) | 95.34 (88.92 to 98.12) | 16.59 (6.37 to 43.22) | 0.1 (0.04 to 0.25) | 37 (24.03) |
| Unexperienced ED sonographers | 81† | 39(48.15) | 87.50 (61.65 to 98.45) | 91.3 (71.96 to 98.93) | 83.65 (57.32 to 95.12) | 93.49 (79.62 to 98.14) | 10.06 (2.64 to 38.32) | 0.14 (0.04 to 0.5) | 42 (51.85) |
*Based on an overall prevalence of appendicitis in this study of 33.7%.
†Examiner experience missing for 107 exams.
LR+, positive likelihood ratio; LR−, negative likelihood ratio; NPV, negative predictive value; PPV, positive predictive value.