PhillyEBM.comLack of Utility of Questionnaire for Detecting Elevated Blood Lead Level
Can a lead-risk questionnaire effectively predict which children will have an elevated blood lead level?
Lead is a neurotoxin that is associated with cognitive deficits in children. Universal blood lead screening is the most effective way to identify children with elevated lead levels, but may not be cost-effective, particularly in populations with a low prevalence of disease. The Center for Disease Control (CDC) 1997 guideline recommends that states and local agencies determine appropriate screening methods for specific populations. One approach recommended by the CDC prescribes blood testing all children in “high-risk” zip-codes, and using a screening questionnaire to select children in the “low-risk” zip-codes who should have blood lead level measurements. Questions used to determine personal-risk of elevated lead level include the year the home was built, whether there were recent renovations, and whether the child had a sibling or close friend with lead poisoning. This CAT sought to determine whether a lead-risk questionnaire could accurately predict which children will have an elevated blood lead level.
Questionnaires used to determine personal risk of elevated lead levels are not sufficiently sensitive to be used as first line screening tools. Using a questionnaire to identify children with elevated lead levels (≥10 µg/dL) would result in failure to identify anywhere from 10 to 60% of children with elevated lead levels. Thus, questionnaires cannot be used to accurately identify children who do not need blood lead level measurement. The decision to implement universal blood lead level screening must be based on the prevalence and cost-effectiveness of screening for elevated lead levels in a particular population.
| First Author, Year | Questionnaire tested | Sample size | Setting | Prev Lead ≥ 10µg/dL % | Sens % | Spec %
|
PPV % | NPV % |
| Schaffer, 1994 | CDC | 476 | Urban | 28 | 70 | 49 | 35 | 81 |
| Binns, 1994 | CDC | 1759 | Suburban | 2.1 | 69 | 70 | 5 | 99 |
| Binns, 1994 | Illinois Specific | 1759 | Suburban | 2.1 | 72 | 64 | 4 | 99 |
| Schaffer, 1996 | CDC | 705 | Rural | 8.4 | 75 | 31 | 8.9 | 93 |
| Schaffer, 1996 | Alternate - locale specific | 705 | Rural | 8.4 | 88 | 53 | 14.6 | 98 |
| France, 1996 | Denver specific | 2978 | Urban | 2.9 | 60 | 36 | 2.6 | 97 |
| Casey, 1994 | CDC | 165 | Urban- High SES | 29 | 40 | 60 | 29 | 71 |
| Rolnick, 1999 | CDC-like | 6469 | Urban/ Suburban | 11.8 | 90 | * | * | * |
| Binns, 1999 | CDC-like | 460 | Urban | 12.1 | 82 | 80 | 15 | 94 |
| Binns, 1999 | CDC-like | 460 | Suburban | 3.5 | 62 | 58 | 5 | 98 |
* Not enough data reported in Rolnick study to calculate specificity, PPV, NPV
"Lead-Risk Questionnaire" with limits of age for all children, then completed search for relevant articles using the “Related Articles” section; also used was Mesh term “Lead poisoning, Nervous System, Childhood”
1) Casey R, Wiley C, Rutstein R, Pinto-Martin J. Prevalence of lead poisoning in an urban cohort of infants with high socioeconomic status. Clin Pediatr (Phila). 1994 Aug;33(8):480-4. [Penn Proxy]
2) France EK, Gitterman BA, Melinkovich P, Wright RA. The accuracy of a lead questionnaire in predicting elevated pediatric blood lead levels. Arch Pediatr Adolesc Med. 1996 Sep;150(9):958-63. [Penn Proxy]
3) Schaffer SJ, Kincaid MS, Endres N, Weitzman M. Lead poisoning risk determination in a rural setting. Pediatrics. 1996 Jan;97(1):84-90. [Penn Proxy]
4) Schaffer SJ, Szilagyi PG, Weitzman M. Lead poisoning risk determination in an urban population through the use of a standardized questionnaire. Pediatrics. 1994 Feb;93(2):159-63. [Penn Proxy]
5) Binns HJ, LeBailly SA, Poncher J, Kinsella TR, Saunders SE. Is there lead in the suburbs? Risk assessment in Chicago suburban pediatric practices. Pediatric Practice Research Group. Pediatrics. 1994 Feb;93(2):164-71. [Penn Proxy]
6) Binns HJ, LeBailly SA, Fingar AR, Saunders S. Evaluation of risk assessment questions used to target blood lead screening in Illinois. Pediatrics. 1999 Jan;103(1):100-6. [Penn Proxy]
7) Rolnick SJ, Nordin J, Cherney LM. A comparison of costs of universal versus targeted lead screening for young children. Environ Res. 1999 Jan;80(1):84-91. [Penn Proxy]
8) Binns HJ, Campbell C, Brown MJ. Interpreting and managing blood lead levels of less than 10 microg/dL in children and reducing childhood exposure to lead: recommendations of the Centers for Disease Control and Prevention Advisory Committee on Childhood Lead Poisoning Prevention. Pediatrics. 2007 Nov;120(5):e1285-98. [Penn Proxy]