Table 3.
The sensitivity, specificity and likelihood ratio values of NLR, CRP and WBC for discrimination of SBI in infants aged 29–90 days (95% CI)
| Parameter and threshold value | Sensitivity | Specificity | LR+ | LR− | PPV | NPV | |
| NLR | >0.85 | 52.2% (40.5 to 63.8) | 58.1% (54.6 to 61.6) | 1.3 (1 to 1.6) | 0.82 (0.6 to 1.1) | 9.9% | 93.2% |
| >1 | 47.8% (36.3 to 59.5) | 65.3% (61.9 to 68.6) | 1.4 (1.1 to 1.8) | 0.8 (0.6 to 1) | 10.8% | 93.4% | |
| >1.5 | 25.4% (16.5 to 36.9) | 82.7% (79.9 to 85.2) | 1.5 (1 to 2.2) | 0.9 (0.8 to 1) | 11.5% | 92.6% | |
| >2 | 16.4% (9.4 to 27.1) | 89.8% (87.4 to 91.7) | 1.6 (0.9 to 2.9) | 0.9 (0.8 to 1.1) | 12.4% | 92.4% | |
| >3 | 9% (4.17 to 18.2) | 96.6% (95.1 to 97.7) | 2.6 (1.1 to 6.2) | 0.94 (0.9 to 1) | 18.9% | 92.3% | |
| CRP (mg/L) | >5 | 74.6% (63.1 to 83.5) | 49% (45.4 to 52.5) | 1.5 (1.3 to 1.7) | 0.5 (0.3 to 0.8) | 11.4% | 95.6% |
| >20 | 44.8% (33.5 to 56.6) | 84.7% (82 to 97.1) | 2.9 (2.1 to 4) | 0.7 (0.5 to 08) | 20.5% | 94.6% | |
| >40 | 20.9% (12.9 to 32.1) | 93.2% (91.2 to 94.8) | 3.1 (1.8 to 5.2) | 0.85 (0.8 to 1) | 21.3% | 93% | |
| >80 | 7.5% (3.2 to 16.3) | 98% (96.8 to 98.8) | 3.8 (1.4 to 10.1) | 0.9 (0.9 to 1) | 25% | 92.3% | |
| ANC (103/µL) | >5 | 52.2% (40.5 to 63.8) | 68.3% (64.9 to 71.5) | 1.7 (1.3 to 2.1) | 0.7 (0.5 to 0.9) | 12.7% | 94.2% |
| >7 | 31.3% (21.5 to 43.2) | 82.6% (79.7 to 85.1) | 1.8 (1.2 to 2.7) | 0.8 (0.7 to 1) | 13.7% | 93.2% | |
| >10 | 13.4% (7.2 to 23.6) | 94.4% (92.5 to 95.8) | 2.4 (1.2 to 4.7) | 0.9 (0.8 to 1) | 17.4% | 92.5% | |
| >15 | 6% (2.4 to 14.3) | 99.1% (98.1 to 99.6) | 6.5 (2 to 21.7) | 1 (0.9 to 1) | 5.5% | 91.9% | |
| WBC (103/µL) |
>10 | 76.1% (64.7 to 84.7) | 37.6% (34.2 to 41.1) | 1.2 (1.1 to 1.4) | 6 (0.4 to 1) | 9.7% | 94.7% |
| >15 | 43.4% (32.1 to 55.2) | 76.3% (73.2 to 79.2) | 1.8 (1.4 to 2.5) | 0.7 (0.6 to 0.9) | 13.9% | 93.9% | |
| >20 | 13.4% (7.2 to 23.6) | 93.5% (91.5 to 95) | 2.1 (1.1 to 4) | 0.9 (0.8 to 1) | 15.4% | 92.5% | |
ANC, absolute neutrophil count; CRP, C reactive protein; LR, likelihood ratio; NLR, neutrophils to lymphocytes ratio; NPV, negative predictive value; PPV, positive predictive value; SBI, serious bacterial infection; WBC, white cell count.