Table 4 Diagnostic performance of CDAs using low-risk criteria
CDA (with low risk criteria) | Low risk criteria | Year of derivation | Derivation Methodology | Sensitivity SBI | Specificity SBI | PPV SBI | NPV SBI | Sensitivity IBI | Specificity IBI | PPV IBI | NPV IBI | Validation (Number of studies) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Low risk: Lab score ≤ 31 point is attributed to positive urine dipstick; 2 points for PCT ≥ 0.5 ng/mL or CRP ≥ 40 mg/L; and 4 points to procalcitonin ≥ 2 ng/mL or CRP ≥ 100 mg/L | 2008 | Regression Analysis | 46%—52% - | 92 – 95% | 76%−80% | 78%—83% | 59.8—88.9% | 84—89% | 8- 15% | 98—99.5% | 3 | |
Morgan Stanley Children Hospital Protocol [40] | Low risk: WBC count between 5000 and 15 000/μL, manual differential of immature: total neutrophil ratio of < 0.2, urinalysis with < 10 WBC/high-power field, normal glucose and liver function tests (If obtained: Normal CSF, Stool and CXR test.) | 2012 | Expert Consensus and Evidence Synthesis | 97.40% | 17.3% | 26.1% | 95.7% | - | - | - | - | 1 |
 > 1 month, well appearing, WCC 5–10^9/L | 2019 | Expert Consensus and Evidence Synthesis | 91% | 9% | 14% | 86% | 93% | 27% | 5% | 99% | 2 | |
NICE NG51 [15] |  > 3 months | 2016 | Expert Consensus and Evidence Synthesis | 100% | 0 | 14% | N/A | - | - | - | - | 1 |
Well appearing, > 21 days + absence of Leukoctouria + PCT > 0.5 ng/mL + (ANC > 10 ^9/L OR CRP > 20 mg/L) | 2014 | Expert Consensus and Evidence Synthesis | 94–98% | 17–68% | 23–37% | 94–99% | 92—100% | 12.4—46.9% | 4- 7.4% | 99.3—100% | 4 | |
7—28 days: Temp < 38.5C, Normal WBC, absolute band count and urinalysis. 22—60 days: Normal WBC, absolute band count and urinalysis | 2016 | Expert Consensus and Evidence Synthesis | - | - | - | - | 96.7% (7–28 days), 91.4% (29–60 days) | 31.7% (7–28 days), 58.5% (29–60 days) | 6.6% (7–28 days), 6.3% (29–60 days) | 99.5% (7–28 days), 99.6% (29–60 days) | 2 | |
Low risk: IBI score of 2 Newborn < 21 d old: 1 point, Body temperature 38.0–38.4 °C: 2 points, Body temperature > 38.4 °C: 4 points, Abnormal urinalysis result: 3 points, Neutrophils > 5.185 *10^9/L: 2 points | 2019 | Regression Analysis | 99–100% | 31–32% | 13% | 82% | 85—100% | 26.6—43% | 2.7—4% | 99.7—100% | 5 | |
Negative urinalysis, ANC < / = 4000/uL and PCT < 0.5 ng/ml | 2019 | Recursive Partitioning | 88.4—98.8% | 36.6—64% | 19.5—41.1% | 86.3—99.8% | 89–100% | 29–63% | 4–5% | 99–100% | 5 | |
 > 1 month and well appearing, negative urinalysis, CRP < 20 mg/L | 2020 | Expert Consensus and Evidence Synthesis | 82% | 14% | 13% | 82% | 99 | 20 | 5 | 100 | 2 | |
 > 21 days, appearing well, ANC < 5.2^9/L, CRP < 20 mg/L, Fever < 38.5 °C | 2021 | Expert Consensus and Evidence Synthesis | 84% | 51% | - | 94% | 93–100% | 17—50.7% | 2.7—4.3% | 99.3—100% | 6 | |
AAP V2 [48] | ANC ≤ 4500/mm3, CRP ≤ 22.2 mg/L, TMax ≤ 39.0 °C | 2025 | Regression Analysis | - | - | - | - | 100% | 83.8% |  | 100% | 0 |
CA FIRST [50] | Aged 29—60, Well appearing, normal urinalysis + bronchiolitis | 2021 | Expert Consensus and Evidence Synthesis | 95% (7–21 days), 100% (22–28 days), 90% (29–60 days) | 27% (7–21 days), 32% (22–28 days), 56% (29–60 days) | 10% (7–21 days), 7% (22–28 days), 6% (29–60 days) | 99% (7–21 days), 100% (22–28 days), 99% (29–60 days) | - | - | - | - | 0 |