| Prediction tool | PPV (%) | NPV (%) | Sensitivity (%) | Specificity (%) | AUC (95% CI) | p Value |
| PSI | 8.8 | 94.2 | 57.6 | 53.4 | 0.55 (0.52 to 0.58) | 0.1 |
| CURB65 score | 7.5 | 92.9 | 33.7 | 67.5 | 0.54 (0.51 to 0.57) | 0.2 |
| CRB65 score | 4.4 | 92.2 | 9.8 | 83.5 | 0.52 (0.49 to 0.55) | 0.5 |
| APACHE II score | 5.7 | 90.2 | 47.8 | 37.7 | 0.41 (0.38 to 0.44) | 0.002 |
| SIRS | 8.2 | 92.9 | 15.2 | 86.7 | 0.57 (0.54 to 0.60) | 0.03 |
| SEWS | 7.9 | 93.2 | 45.7 | 58.2 | 0.53 (0.50 to 0.56) | 0.3 |
The p value refers to comparison between the receiver operator characteristic curve and the null hypothesis.
APACHE II, Acute Physiology and Chronic Health Evaluation II; AUC, area under the receiver operator characteristic curve; CRB65, New onset confusion, Respiratory rate ≥30 breaths/min, Systolic blood pressure <90 mm Hg and/or diastolic blood pressure ≤60 mm Hg and age ≥65 years; CURB65, New onset confusion, urea >7 mmol/l, Respiratory rate ≥30 breaths/min, Systolic blood pressure <90 mm Hg and/or diastolic blood pressure ≤60 mm Hg and age ≥65 years; NPV, negative predictive value; PPV, positive predictive value; SEWS, standardised early warning score; SIRS, systemic inflammatory response syndrome.