. Author manuscript; available in PMC: 2013 Oct 4.

Published in final edited form as: Arch Pediatr Adolesc Med. 2012 Aug;166(8):738–744. doi: 10.1001/archpediatrics.2012.490

Table 4.

Refinement of Low Risk Appendicitis Rule

Model	Model components	Cohort identified as low risk	Sensitivity [95% CI]	Specificity [95% CI]	NPV [95% CI]	PPV [95% CI]
Validated rule	ANC <= 6.75 × 10³/µL Nausea Maximal tenderness in RLQ	531 without appendicitis 42 with appendicitis	95.5% [93.9–96.7]	36.3% [33.9–38.9]	92.7% [90.1–94.6]	48.8% [46.5–51.1]
Refinement	ANC <=6.75 × 10³/µL Maximal tenderness in RLQ Pain with walking/jumping or coughing	381 without appendicitis 19 with appendicitis	98.1% [97.0–98.9]	23.7% [21.7–25.9]	95.3% [92.3–97.0]	44.9% [42.8–47.0]

All values reported with 95% confidence interval