CLN Daily 2025
Despite worldwide efforts to rid our environment of lead — a naturally occurring metal with no physiological function in the human body — lead poisoning is still a public health problem. In fact, more than 1.5 million deaths globally were attributed to lead exposure in 2021, according to the World Health Organization (WHO).
Children are especially vulnerable, since high lead levels can damage their developing brains and central nervous systems. While it’s hard to pinpoint how many children have been exposed, “there are still millions of kids with blood levels that are considered toxic,” said Amy Pyle-Eilola, PhD, DABCC, FADLM, director of clinical chemistry at Nationwide Children's Hospital in Columbus, Ohio, who will present on this topic at ADLM 2025 (formerly the AACC Annual Scientific Meeting & Clinical Lab Expo).
In her roundtable session, Pyle-Eilola will discuss the implications of lead poisoning, the regulatory requirements for testing and reporting blood lead levels (BLLs) in children, and the analytical details of measuring blood lead. In addition to describing the clinical significance of lead toxicity, she will talk about how it disproportionally affects those in marginalized communities.
Since the Lead-Based Poison Prevent Act was passed in 1971, making BLL testing a standard practice in the U.S., the toxicity threshold has changed as tests for BLL have become more sensitive. Today, it’s 3.5 μg/dL, which is “around what we’re able to detect,” Pyle-Eilola said, and she anticipates this value will continue to evolve.
“The technology will improve and we’ll get more sensitive and be able to measure lower,” she said. Nevertheless, studies have tied a very low BLL with developmental outcomes, especially in behavioral health. “Really, any measurable lead is considered too high,” she said.
For example, studies have linked an elevated BLL with ADHD and antisocial behavior. In addition, childhood lead exposure is associated with higher rates of delinquency and criminal behavior in adults. Overall, the WHO estimates that lead exposure accounted for more than 33 million years lost to disability (disability-adjusted life years, or DALYs) worldwide in 2021.
“As we have been able to decrease the number of individuals who are exposed to high levels of lead, we have essentially been able to improve the population IQ,” she said.
While lead has been removed from common liquids and materials like gasoline and paint, it remains present in our environment, especially in homes or structures built before 1978 that haven’t gone through lead remediation. Many older buildings — including schools — still have lead pipes. Indeed, the Natural Resources Defense Council estimates that 12.8 million lead pipes are in service in the U.S.
That’s why lead poisoning is an equity issue, Pyle-Eilola explained. Those who live in areas with poverty are most affected. “These things really go hand in hand with elevated blood levels. This is important for people to at least be very cognizant of.”
Unfortunately, lead poisoning probably won’t go away anytime soon. “Even though we are now worried about kids at really low BLLs, we’re still catching some much higher, acutely toxic cases,” where a patient needs to be brought into the hospital for treatment, according to Pyle-Eilola. “Until lead is gone from the environment, we’re always going to have to worry about lead toxicity.”
Jen A. Miller is a freelance journalist who lives in Audubon, New Jersey. +Bluesky: @byjenamiller.bsky.social