A comparison of screening strategies for elevated blood lead levels.

Abstract

To calculate and compare the average expected cost per child screened (hereafter referred to as COST) among various screening strategies. 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. 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%. 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.