A comparison of screening strategies for elevated blood lead levels
J. R. Campbell, M. Paris and S. J. Schaffer
Department of Pediatrics, University of Rochester School of Medicine and Dentistry, NY, USA.
OBJECTIVE: To calculate and compare the average expected cost per child
screened (hereafter referred to as COST) among various screening
strategies. DESIGN: A decision analysis of 5 strategies: (1) conduct risk
assessment and screen high-risk children by venipuncture, low-risk children
by fingerstick; (2) screen all children by fingerstick; (3) screen all
children by venipuncture; (4) conduct risk assessment, screen high-risk
children by fingerstick; and (5) conduct risk assessment, screen high-risk
children by venipuncture. We assumed all fingerstick blood lead levels of
0.72 mumol/L or higher (> or = 15 micrograms/dL) would be confirmed by
venipuncture. Baseline variables taken from the literature included
prevalence of elevated blood lead levels in the pediatric population (2%),
sensitivity and specificity of fingerstick blood lead assay (90% each),
specificity of risk assessment (50%), sensitivity of risk assessment at
blood lead levels of 0.48 to 0.68 mumol/L (10-14 micrograms/dL) and 0.72
mumol/L or higher (> or = 15 micrograms/dL) (65% and 85%, respectively),
cost of blood lead assay ($6), cost to obtain blood by venipuncture ($4)
and fingerstick ($2), and cost to get a child who has a fingerstick blood
lead level of 0.72 mumol/L or higher (> or = 15 micrograms/dL) to return
($0.18). Sensitivity analysis determined whether selected variables
affected the COST. RESULTS: The COSTs for strategies 1 through 5 were
$9.07, $8.16, $10, $4.13, and $5.04, respectively. Among the universal
strategies, screening children by fingerstick had the lowest COST at a
prevalence of less than 38% and fingerstick blood lead assay a specificity
of greater than 62%. Among the selective strategies, screening high-risk
children by fingerstick had the lowest COST at a prevalence of less than
38% and fingerstick blood lead an assay specificity of greater than 63%.
CONCLUSION: At a readily attainable specificity of the fingerstick blood
lead assay, practices serving a patient population with a prevalence of
elevated blood lead levels of less than 38% will have the lowest COST when
a fingerstick screening strategy is used.
