The accuracy of a lead questionnaire in predicting elevated pediatric blood lead levels.

OBJECTIVES

To determine the prevalence of elevated blood lead levels and to evaluate the accuracy of a lead screening questionnaire in a western United States urban inner-city pediatric population.

DESIGN

A convenience sample of children between the ages of 6 months and 6 years seen for a well-child visit were enrolled. Venous blood lead levels were measured and a lead screening questionnaire was completed.

SETTING

The primary care clinics of the 10 community health centers of the city and county of Denver, Colorado. Approximately 85% of children receiving services are below the 150% poverty level and 54% are insured through the state's Medicaid program.

SUBJECTS

A total of 2978 children seen for a well-child visit from February 1993 to January 1994.

MAIN OUTCOME MEASURES

The prevalence of elevated blood lead levels and the operating characteristics of both the Centers for Disease Control and Prevention lead screening questionnaire and the complete questionnaire used in Denver, using venous blood lead levels as the criterion standard.

RESULTS

The mean blood lead level was 0.20 mumol/L (4.19 micrograms/dL). Eighty-five children had blood lead levels of 0.48 mumol/L (10 micrograms/dL), representing 2.9% of the study group (95% confidence interval [CI], 2.3-3.5). Only 0.3% of the cohort had blood lead levels greater than 0.96 mumol/L (20 micrograms/dL). The sensitivity, specificity, and positive predictive value of the Centers for Disease Control and Prevention questionnaire was 57%, 51%, and 3%, respectively. The sensitivity, specificity, and positive predictive value of the complete questionnaire was 59.7%, 36%, and 2.6%, respectively. The marginal cost of identifying a child with a blood lead level greater than 0.96 mumol/L (20 micrograms/dL) was $4925.

CONCLUSIONS

Few of the low-income children in this study had blood lead levels greater than 0.48 mumol/L (10 micrograms/dL). The questionnaire did little better than chance at predicting the presence or absence of elevated blood lead levels and cannot replace a blood lead level test for childhood lead screening in this community.