Health Officials Lower Threshold for Lead Poisoning in Children

The Centers for Disease Control and Prevention (CDC) recently lowered the threshold for blood lead levels in young children, a change that will likely identify more children as having lead poisoning. Children with blood lead levels above the new threshold are considered to have levels higher than most other children in the U.S.

Over the past several years, public health officials have looked at data on lead levels in children and adjusted the cutoff level for lead poisoning accordingly. The cutoff was last adjusted more than 9 years ago when the CDC lowered the value from 10 micrograms per deciliter (mcg/dL) to 5 mcg/dL. On October 28, 2021, the cutoff was further lowered to 3.5 mcg/dL.

The CDC made the decision to lower the blood lead threshold following a recommendation from the Lead Exposure and Prevention Advisory Committee (LEPAC). The new cutoff is based on the 97.5th percentile of blood lead levels in American children ages 1 to 5 years old. This means that children with blood lead levels at or above 3.5 mcg/dL are in the top 2.5% of those with the highest blood lead levels. The percentile was calculated from data collected from 2015 to 2016 and from 2017 to 2018 by the National Health and Nutrition Examination Survey (NHANES).

While no level of lead is considered safe for children, health officials use the threshold to identify children who have been exposed to the toxic metal. If a child’s lead level is above the cutoff, officials look to determine the source of lead exposure and remove it. Children who are found to have high blood lead levels are monitored and some may require treatment.

Children can be exposed to lead through their environment. Some houses built before 1978 may still contain lead-based paint and contaminated dust or paint chips. Children can breathe in lead dust or swallow it when they put their hands in their mouths. Contaminated drinking water has also been found to be a source of lead poisoning. In one widely-reported case, residents of Flint, Michigan were exposed to high lead levels due to contaminated water.

Although lead can be harmful for anyone, it is especially toxic for children because they are still growing and because it can build up in the body over time. Even small amounts of lead can damage developing brains and nervous systems as well as the heart, kidneys, and the liver. Lead poisoning can cause life-long health issues, including slow growth, behavior and learning disabilities, hyperactivity, and speech and hearing problems.

Because children are especially at risk for lead’s toxic effects, they are routinely assessed for possible exposure and may have their blood tested for lead if they are found to be at risk. Typically, a blood sample from a fingerstick is first screened. If that level is elevated, the result is confirmed by testing a sample of blood taken from a vein. Accurate blood lead testing is critical, especially now that the threshold has been lowered and tests are required to detect smaller amounts of lead. A recent recall of lead testing kits has highlighted the importance of accurate screening tests for children.

While accurate testing and identifying and removing sources of lead exposure are important strategies, preventing exposure to lead in the first place is key. The CDC provides a resource for parents that lists the steps they can take to make their childrens’ homes and environments safe from lead.