Table 4.

Deterministic Sensitivity Analyses^*

Parameter	Base Case (Range)	Threshold, CT Most Effective Strategy: Willingness To Pay $50,000	Threshold, CT Most Effective Strategy: Willingness To Pay $100,000
Probabilities
Prevalence of Appendicitis	0.30 (0.24–0.37)	never	never
CT
Sensitivity	0.86 (0.64–0.97)	never	never
Specificity	0.97 (0.86–1.00)	> 0.991	> 0.993
MRI
Sensitivity	0.80 (0.44–0.97)	never	never
Specificity	0.99 (0.94–1.00)	< 0.969	< 0.967
Costs
CT	$694 ($480–$941)	never	never
MRI	$1,274 ($940 – $10,441)	> $3,98**	> $7,068***

^*Depicted here are the model parameters for which there existed threshold values within the uncertainty ranges noted in Table 1.

^**3.1x Centers for Medicare and Medicaid Services cost for MRI with other test costs conservatively held at 1.0x CMS

^***5.6x Centers for Medicare and Medicaid Services cost for MRI with other test costs conservatively held at 1.0x CMS