Blood Lead Reference Value

In 2012, CDC updated its recommendations on children’s blood lead levels. CDC now uses a blood lead reference value of 5 micrograms per deciliter (µg/dL) to identify children with blood lead levels that are much higher than most children’s levels. This new level is based on the U.S. population of children ages 1-5 years who are in the highest 2.5% of children when tested for lead in their blood.

CDC’s Blood Lead Reference Value

The blood lead reference value is based on the 97.5th percentile of the National Health and Nutrition Examination Survey (NHANES) blood lead distribution in children ages 1-5 years. The current reference value is based on NHANES data from 2007-2008 and 2009-2010.

NHANES is a population-based survey to assess the health and nutritional status of adults and children in the United States and determine the prevalence of major diseases and risk factors for diseases.

CDC will assess the NHANES data every 4 years using the two most recent survey cycles of available data to determine if the blood lead reference value should be updated.

Previous Terminology

Until 2012, children were identified as having a blood lead “level of concern” if the test result was 10 or more micrograms per deciliter (µg/dL) of lead in blood. CDC is no longer using the term “level of concern” and is instead using the reference value to identify children who have more lead in their blood than most children. Recommended follow-up actions are based on confirmed blood lead levels.

In the past, blood lead level tests below 10 micrograms per deciliter of lead in blood may, or may not, have been reported to parents. The new lower value means that more children will likely be identified as having lead exposure allowing parents, doctors, public health officials, and communities to take action earlier to reduce the child’s future exposure to lead.

What has not changed is the recommendation for when to use medical treatment for children. Experts recommend chelation therapy when a child is found with a test result of greater than or equal to 45 micrograms per deciliter of lead in blood.

Additional Resources