The U.S. Preventive Services Task Force (USPSTF) has concluded that "current evidence is insufficient to assess the balance of benefits and harms" of routine screening for elevated blood lead levels in asymptomatic children and pregnant women. Accordingly, the task force's new recommendation on screening is a grade of "I," meaning insufficient evidence one way or the other. This updates its 2006 recommendation of "D," which was meant to discourage routine screening of asymptomatic children one to five years old at average risk and asymptomatic pregnant women.
The "I" grade does not mean that screening is unnecessary or should not be offered. Instead, it acknowledges that evidence is lacking to definitively recommended for or against screening. This new grade also highlights knowledge gaps and areas for further study. Overall, there is universal agreement that no level of lead in blood is safe, and more policies are needed to protect children from lead exposure.
Since 2006, the reference level considered "elevated" in children has fallen from 10 to 5 [micro]g/dL. More sources of lead have also been identified over the years that require further study, as do methods to treat lead toxicity and improve health outcomes.
"We need more research to determine what primary care clinicians can do to help prevent and treat health problems related to lead exposure," said Alex Krist, USPSTF vice chair and professor of family medicine at Virginia Commonwealth University. "Until there is more research, those working in primary care should use their best judgment about whether or when to screen for blood levels, and all nurses should keep up to date on whether there are concerns about lead in their community."
Elevated levels of lead in the blood affect the cardiovascular, renal, and hepatic systems, and very high levels can cause death or long-term neurologic symptoms in children, says the USPSTF. Blood lead levels as low as 5 [micro]g/dL have been associated with behavioral disorders in children.-Carol Potera
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