Lab Advisory: CDC Updates Blood Lead Reference Value

The U.S. Centers for Disease Control and Prevention (CDC) recently updated its blood lead reference value (BLRV) from 5 µg/dL to 3.5 µg/dL in response to the Lead Exposure Prevention and Advisory Committee (LEPAC) recommendation made on May 14, 2021. The BLRV is intended to identify children with higher levels of lead in their blood compared to most children, based on the 97.5th percentile of the blood lead level (BLL) distribution in U.S. children ages 1–5 years.

The new BLRV of 3.5 μg/dL may create challenges for laboratories that perform blood lead testing. Laboratories may encounter increased workloads because of additional repeat and confirmatory testing. Some laboratories may need to

• Reduce lower reporting limit policies
• Adopt new repeat testing practices
• Improve limits of detection of laboratory-developed tests
• Acquire new instrumentation
• Validate new laboratory-developed tests
• Clarify minimum volume requirements for pediatric capillary samples
• Update data handling systems to report blood lead levels to the tenth of a µg/dL (i.e., X.X µg/dL) if they currently only report BLLs in integer values
• Take extra steps to prevent common lead contamination in laboratory consumables and the laboratory environment to prevent false positives in reporting at these lower levels

Online resources:

• CDC Childhood Lead Poisoning Prevention Program
• Screening Young Children for Lead Poisoning: Guidance for State and Local Public Health Officials (see Appendix C “The Lead Lab”)
• Laboratory Methods - Analysis of whole human blood for Pb, Cd, Hg, Se, and Mn by ICP-DRC-MS for biomonitoring and acute exposures
• Laboratory Response Network – Chemical (LRN-C) Program
• Association of Public Health Laboratories (APHL) – National Biomonitoring Network
• APHL – Biomonitoring Toolkit
• Clinical and Laboratory Standards Institute (CLSI) - CLSI C40-A2 "Measurement Procedures for the Determination of Lead Concentrations in Blood and Urine; Approved Guideline - Second Edition" October 2013.

For questions about the latest analytical method documentation, contact CDC’s Division of Laboratory Sciences Inorganic and Radiation Analytical Toxicology Branch.