The health department of a major city wants to start testing children for lead poisoning. Two tests are available: the free erythrocyte protoporphyrin (FEP) assay and the more expensive direct blood lead assay. Children identified as positive after screening must have a confirmatory work-up at the hospital. The department's goal is to identify as many lead-poisoned children as possible, but the lead-screening program must compete with other programs. Several strategies for using these tests are evaluated:
Costs for Screening 1000 children for Lead Poisoning
Screening Strategy Costs # of cases detected
A) Screening FEP only $25,000 75
B) Screening FEP, then blood assay if FEP+ $40,000 75
C) Blood lead assay only $60,000 100
D) FEP first, confirm if FEP+, blood lead assay if FEP- $75,000 100
a. Should any strategies be removed from consideration? Why?
b. Restructure the above table for the remaining strategies. Calculate the average CE ratios and the incremental CE ratios. (Express ratios in dollars per case detected)
c. Show these results graphically. Indicate the relationships between the strategies in part b and label average and incremental CE ratios on the graph. Also depict the location of any programs that were removed from consideration in part a.
d. What factors will influence your choice of strategy?