Receiver operating characteristics curve analysis for discriminating bacterial infection cases from other conditions
| Onset of symptoms | No. of cases (%) | No. of controls (%) | Variable/combination | AUC (95% CI) | ||
|---|---|---|---|---|---|---|
| <24 hr | 94 (9.5) | 891 (90.5) | SAA (mg/L) | 0.8200 (0.7740 to 0.8660) | <0.0001 | - |
| CRP (mg/L) | 0.8302 (0.7849 to 0.8755) | <0.0001 | 0.4609 | |||
| ESR (mm/hr) | 0.7052 (0.6499 to 0.7605) | <0.0001 | <0.0001 | |||
| WBC count (×103/µL) | 0.7052 (0.6439 to 0.7664) | <0.0001 | 0.0026 | |||
| Neutrophil count (×103/µL) | 0.7357 (0.6790 to 0.7923) | <0.0001 | 0.0127 | |||
| SAA+ESR+CRP+neutrophil | 0.8455 (0.8052 to 0.8859) | <0.0001 | 0.0688 | |||
| ≥24 hr | 90 (21.7) | 325 (78.3) | SAA (mg/L) | 0.8349 (0.7934 to 0.8764) | <0.0001 | - |
| CRP (mg/L) | 0.8085 (0.7593 to 0.8577) | <0.0001 | 0.0416 | |||
| ESR (mm/hr) | 0.6872 (0.6260 to 0.7484) | <0.0001 | <0.0001 | |||
| WBC count (×103/µL) | 0.6733 (0.6051 to 0.7415) | <0.0001 | <0.0001 | |||
| Neutrophil count (×103/µL) | 0.7038 (0.6385 to 0.7691) | <0.0001 | 0.0002 | |||
| SAA+ESR+CRP+neutrophil | 0.8353 (0.7930 to 0.8776) | <0.0001 | 0.9651 | |||
| All | 184 (13.1) | 1,216 (86.9) | SAA (mg/L) | 0.8400 (0.8102 to 0.8698) | <0.0001 | - |
| CRP (mg/L) | 0.8337 (0.8020 to 0.8654) | <0.0001 | 0.4908 | |||
| ESR (mm/hr) | 0.7217 (0.6830 to 0.7604) | <0.0001 | <0.0001 | |||
| WBC count (×103/µL) | 0.6721 (0.6263 to 0.7178) | <0.0001 | <0.0001 | |||
| Neutrophil count (×103/µL) | 0.7011 (0.6578 to 0.7444) | <0.0001 | <0.0001 | |||
| SAA+ESR+CRP+neutrophil | 0.8479 (0.8199 to 0.8759) | <0.0001 | 0.3488 |
Abbreviations: AUC, area under the curve; CI, confidence interval; SAA, serum amyloid A; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; WBC, white blood cells.
*Compared the AUC of each variable with that of SAA.