Table 1. Summary of key parameters used in modeling the time and financial cost of enrollment.

For detailed descriptions of parameter estimates, see Appendix B for parameters that affect time and Appendix C for parameters that affect financial cost. A web-based application was developed that allows investigators to input their own values for these parameters into the model.

Parameter type	Parameter	Value
Target enrollment	Number of amyloid PET+ individuals who meet study criteria	100
Characteristics of potentially eligible cohort (after initial phone call)	Amyloid PET positive, meets study criteria Amyloid PET positive, does not meet study criteria Amyloid PET negative, meets study criteria Amyloid PET negative, does not meet study criteria	25% 5% 55% 15%
AD blood test accuracy	Sensitivity of AD blood test for brain amyloidosis Specificity of the AD blood test for brain amyloidosis	85% 80%
Step 1: Intake	Percent of individuals called who meet eligibility criteria and follow-up for a screening visit	75%
	Initial phone calls per day	1.3
	Cost of initial phone call without AD blood test scheduling	$80
	Cost of initial phone call with AD blood test scheduling	$175
Step 2: Screening	Waiting time between initial phone call and screening visit	37 days
	Waiting time between initial phone call/AD blood test and screening visit	47 days
	Screening visits per day	1.2
	Cost of screening visit without routine laboratory tests	$1,326
	Cost of screening visit with routine laboratory tests	$2,209
	Cost of AD blood test	$540
Step 3: Amyloid PET	Waiting time between screening visit and amyloid PET scan	30 days
	Amyloid PET scans per day	0.34
	Cost of amyloid PET scan	$6,487