Predictive value of clinical variables for serious bacterial infection
| Clinical variable | Sensitivity, % (95% CI) | Specificity, % (95% CI) | PPV, % (95% CI) | NPV, % (95% CI) | LR+ (95% CI) | LR− (95% CI) |
|---|---|---|---|---|---|---|
| Risk factor for infection | 10.8 (4.8 to 20.2) | 97.6 (96.8 to 98.2) | 15.1 (6.7 to 28.0) | 96.5 (95.6 to 97.3) | 4.5 (3.3 to 6.2) | 0.91 (0.67 to 1.25) |
| Developmental delay | 5.4 (1.5 to 13.3) | 98.7 (98.1 to 99.2) | 14.3 (4.0 to 32.7) | 96.4 (95.4 to 97.2) | 4.2 (4.2 to 4.3) | 0.96 (0.95 to 0.97) |
| Consciousness level | ||||||
| Not alert* | 2.8 (0.34 to 9.7) | 98.8 (98.2 to 99.3) | 8.3 (1.0 to 27.0) | 97.5 (96.7 to 98.1) | 2.4 (1.7 to 3.3) | 0.98 (0.7 to 1.4) |
| No response to voice | 2.8 (0.34 to 9.7) | 99.8 (99.5 to 99.9) | 33.3 (4.3 to 77.7) | 96.4 (95.4 to 97.2) | 13.0 (9.2 to 18.2) | 0.97 (0.69 to 1.4) |
| Unresponsive | 0.0 (0.0 to 5.0)† | 99.9 (99.7 to 100.0) | 0.0 (0.0 to 97.5)† | 96.1 (95.2 to 97.0) | 0.0 | 1.0 |
| State variation | ||||||
| Eyes close briefly or falls asleep | 8.1 (3.0 to 16.8) | 98.6 (98.0 to 99.1) | 18.8 (7.2 to 36.4) | 96.4 (95.5 to 97.2) | 5.8 (7.0 to 4.9) | 0.93 (0.78 to 1.1) |
| Falls asleep | 0.0 (0.0 to 4.9)† | 99.9 (99.7 to 100.0) | 0.0 (0.0 to 97.5)† | 96.2 (95.2 to 97.0) | 0.0 | 1.0 |
| Temperature | ||||||
| ≥37.5°C | 60.8 (48.8 to 72.0) | 64.5 (62.2 to 66.7) | 6.5 (4.8 to 8.6) | 2.4 (1.6 to 3.4) | 1.7 (0.65 to 4.5) | 0.61 (0.23 to 1.61) |
| ≥38.5°C | 37.8 (26.8 to 49.9) | 84.8 (83.1 to 86.4) | 9.2 (6.2 to 13.0) | 97.1 (96.1 to 97.9) | 2.5 (1.1 to 5.7) | 0.73 (0.32 to 1.7) |
| Tachycardia | 63.9 (50.6 to 75.8) | 60.9 (58.4 to 63.3) | 6.0 (4.3 to 8.1) | 97.7 (96.6 to 98.6) | 1.6 (0.67 to 4.0) | 0.59 (0.24 to 1.5) |
| Capillary refill time ≥2 s | 9.7 (4.0 to 19.0) | 98.1 (97.3 to 98.7) | 17.5 (7.3 to 32.8) | 96.3 (95.3 to 97.1) | 5.1 (4.0 to 6.5) | 0.92 (0.72 to 1.2) |
| Hydration status | ||||||
| Dry mucous membranes | 21.6 (12.9 to 32.7) | 94.9 (93.8 to 95.9) | 14.4 (8.5 to 22.4) | 96.8 (95.9 to 97.6) | 4.3 (2.3 to 7.8) | 0.83 (0.45 to 1.5) |
| Reduced skin turgor | 5.4 (1.5 to 13.3) | 99.7 (99.4 to 99.9) | 44.4 (13.7 to 78.8) | 96.4 (95.4 to 97.2) | 20.2 (20.1 to 20.4) | 0.95 (0.94 to 0.96) |
| Hypotension | 0.0 (0.0 to 4.9)† | 99.8 (99.5 to 99.9) | 0.0 (0.0 to 60.2)† | 96.2 (95.3 to 97.0) | 0.0 | 1.0 |
| Tachypnoea | 71.6 (59.3 to 82.0) | 41.9 (39.4 to 44.4) | 5.2 (3.8 to 6.8) | 97.1 (95.5 to 98.2) | 1.2 (0.47 to 3.2) | 0.68 (0.26 to 1.8) |
| Hypoxia | ||||||
| Mild or severe | 33.8 (23.2 to 45.7) | 83.7 (81.9 to 85.3) | 7.6 (4.9 to 10.9) | 97.0 (96.0 to 97.8) | 2.1 (0.95 to 4.5) | 0.79 (0.36 to 1.7) |
| Severe | 12.2 (5.7 to 21.8) | 97.0 (96.1 to 97.7) | 13.6 (6.4 to 24.3) | 966 (95.6 to 97.3) | 4.0 (2.8 to 5.8) | 0.91 (0.63 to 1.3) |
| Rash | ||||||
| Purpuric rash | 1.5 (0.04 to 8.0) | 99.1 (98.5 to 99.5) | 6.3 (0.2 to 30.2) | 96.0 (95.0 to 96.9) | 1.6 (0.8 to 3.2) | 0.99 (0.50 to 2.0) |
| Petechial rash | 2.9 (0.4 to 10.2) | 97.6 (96.7 to 98.3) | 4.8 (0.6 to 16.2) | 96.0 (95.0 to 96.9) | 1.1 (0.79 to 1.6) | 1.0 (0.71 to 1.4) |
| Macular rash | 5.4 (1.5 to 13.3) | 89.9 (88.4 to 91.2) | 2.1 (0.6 to 5.2) | 96.0 (95.0 to 96.9) | 0.53 (0.53 to 0.54) | 1.1 (1.0 to 1.1) |
* Not alert indicates only responds to voice or pain, or unresponsive.
† One sided, 97.5% CI.
LR+, likelihood ratio of a positive test; LR−, likelihood ratio of a negative test; NPV, predictive value of a negative test; PPV, predictive value of a positive test.