Table 2.
Test characteristics of CRP for appendicitis in children with acute abdominal pain at different cut-off levels.
| Cut-off | Sensitivity (95%CI) |
Specificity (95%CI) |
LH+ (95%CI) |
LH− (95%CI) |
PPV (95%CI) |
NPV (95%CI) |
|---|---|---|---|---|---|---|
| ≥6 mg/L | 0.90 (0.81–0.96) |
0.71 (0.68–0.73) |
3.05 (2.69–3.45) |
0.14 (0.07–0.29) |
0.18 (0.14–0.22) |
0.99 (0.98–1.00) |
| ≥10 mg/L | 0.87 (0.77–0.94) |
0.77 (0.74–0.79) |
3.76 (3.26–4.35) |
0.17 (0.09–0.31) |
0.21 (0.16–0.26) |
0.99 (0.98–1.00) |
| ≥20 mg/L | 0.74 (0.62–0.84) |
0.85 (0.82–0.87) |
4.85 (3.97–5.93) |
0.30 (0.20–0.45) |
0.25 (0.20–0.32) |
0.98 (0.97–0.99) |
| ≥30 mg/L | 0.63 (0.51–0.74) |
0.89 (0.87–0.91) |
5.65 (4.39–7.26) |
0.42 (0.31–0.57) |
0.28 (0.21–0.36) |
0.97 (0.96–0.98) |
| ≥40 mg/L | 0.54 (0.42–0.66) |
0.92 (0.90–0.94) |
6.91 (5.11–9.35) |
0.50 (0.38–0.61) |
0.33 (0.24–0.42) |
0.97 (0.95–0.98) |
| ≥50 mg/L | 0.41 (0.30–0.54) |
0.94 (0.93–0.96) |
7.19 (4.94–10.4) |
0.62 (0.51–0.76) |
0.33 (0.24–0.44) |
0.96 (0.94–0.97) |
| ≥80 mg/L | 0.27 (0.17–0.39) |
0.97 (0.95–0.98) |
8.03 (4.84–13.3) |
0.75 (0.65–0.87) |
0.36 (0.23–0.50) |
0.95 (0.94–0.96) |
| ≥100 mg/L | 0.19 (0.11–0.30) |
0.98 (0.97–0.99) |
8.90 (4.65–17.0) |
0.83 (0.74–0.93) |
0.38 (0.22–0.56) |
0.95 (0.93–0.96) |
CI: Confidence interval; CRP: C-reactive protein; LH+: positive likelihood ratio; LH−: negative likelihood ratio; NPV: negative predictive value; PPV: positive predictive value.