Se (%) | Sp (%) | PPV (%) | NPV (%) | LR+ | LR− | AUROC | 95% CI | P value | |

ROX index from SpO_{2} | 75.7 | 46.8 | 14.3 | 94.2 | 1.42 | 0.52 | 0.64 | 0.57 to 0.70 | <0.001 |

CURB-65 | 83.0 | 54.2 | 17.5 | 96.4 | 1.81 | 0.31 | 0.76 | 0.71 to 0.81 | <0.001 |

AUROC, area under the curve of receiver operating characteristics; CURB-65, confusion, urea level, respiratory rate, systolic or diastolic blood pressure, 65 years or older; LR−, likelihood ratio of a negative test; LR+, likelihood ratio of a positive test; NPV, negative predictive value; PPV, positive predictive value; ROX index,

*R*espiratory rate-*OX*ygenation index; Se, sensitivity; Sp, specificity; SpO_{2}, oxygen saturation by pulse oximetry.