Lead Testing Under-Used; Geographic Variability in Elevated Levels Can Target Testing

While the water crisis in Flint, Mich. dominated headlines at the beginning of the year, that city is not alone in concerns over lead harming young children. Over the past four decades, blood lead concentrations among U.S. children have declined due to the elimination of lead from gasoline, paints, and other consumer products. Yet, there are worrisome population pockets of young children with elevated blood levels of lead, particularly among those living in poverty in older homes.

New data shows a significant lead problem is potentially harming millions of U.S. children and that blood lead screening is under-used. As was the case in Flint, lead can leach into drinking water from pipes—a problem similarly discovered recently in Mississippi, Ohio, New Jersey, and Oregon schools. Lead can also be ingested through old houses’ remaining lead paint, as well as from contaminated soil and dust. A blood lead test is a cheap and reliable way to identify a lead-poisoned child.

Preferred Sample Guidance
The U.S. Centers for Disease Control and Prevention (CDC) say there is no safe blood lead level in children, and research has identified a blood lead level of 5 μg/ dL or more as a threshold to trigger the need for clinical and public health interventions. Children are most at-risk for lead-related complications, including lower IQ, in early childhood.

In 1991, the CDC recommended universal blood lead testing for children. Because of wide variation in lead exposure, in 2005 the American Academy of Pediatrics (AAP) recommended that states and cities develop their own lead screening strategy based on local data. The AAP, like the CDC, recommended universal, blood-based, lead screening of children living in communities with more than 27 percent of housing built before 1950 or a prevalence of blood lead concentrations 10 μg/dL or higher in children 12 to 36 months old of 12 percent or greater.

AAP’s Environmental Health Council published a policy statement on the prevention of childhood lead toxicity in the June issue of Pediatrics. The paper, written by lead author Bruce Perrin Lanphear, M.D. makes several new recommendations regarding testing asymptomatic children for elevated blood lead concentrations.

AAP calls on the Centers for Medicare & Medicaid Services to “expeditiously revise” current regulations for allowable laboratory error permitted in blood lead proficiency testing programs from ±4 μg/dL to ±2 μg/dL for blood lead concentrations of 20 μg/dL or less. AAP says that this range of error can result in children’s blood lead levels being misclassified.

Clinically, AAP says pediatricians are in a unique position to work with public health officials to improve testing adherence and refer for environmental assessments of older housing. Some specific clinical testing recommendations include:

• Testing asymptomatic children for elevated blood lead concentrations according to federal, local, and state requirements and testing immigrant, refugee, and internationally adopted children when they arrive in the United States because of their increased risk.
• Working with public health officials to conduct surveys of blood lead concentrations among a randomly selected, representative sample of children in their states or communities at regular intervals to identify trends in blood lead concentrations.
• Monitoring children who have blood lead concentrations 5 μg/dL or higher until environmental investigations and remediation are complete and blood lead concentrations decline.
• Screening children for iron deficiency and insufficient dietary calcium intake.

“In the primary care office, primary prevention begins with education and counseling,” writes the AAP’s Council on Environmental Health. “Blood lead surveillance data can be used to identify cities, communities, or housing units at higher than typical risk for lead poisoning. Technologies using geographic information system-based analyses and surveillance from electronic medical records are important tools to identify at-risk children who should have their blood lead concentration measured.”

Evidence of Under-Testing
In addition to the CDC’s call for universal testing, blood lead tests are mandated for all children in 11 U.S. states (Alabama, Connecticut, Delaware, Iowa, Louisiana, Maryland, Massachusetts, New Jersey, New York, Rhode Island, Vermont) and Washington, D.C. Additionally, Medicaid requires that enrolled children be tested for lead toxicity at ages one and two years as part of its Early and Periodic Screening, Diagnostic and Treatment) benefit. Yet, new evidence shows that testing is inconsistently performed.

On June 9, Reuters published the results of their investigation showing that millions of children are falling through the lead testing safety net, leaving them vulnerable to poisoning, beyond the extent seen in Flint. The news agency reviewed data from state health departments, the Centers for Medicare and Medicaid Services, and the CDC. The Reuters investigation found that:

• Only 41 percent of Medicaid-enrolled one- and two-year-olds had been tested, as required.
• In some states requiring tests, more than half the children were not tested.
• Medicaid claims data showed wide variability in screening. In California, Medicaid paid for enough lead tests to cover just one in three enrollees in 2014, whereas Massachusetts screens around 80 percent of children.
• Utah, Kansas, and Alaska report not recognizing or following a federal requirement to test Medicaid children.

Some of the reasons cited for under-testing include; Some doctors don’t order the tests or are unaware of the rules, parents don’t follow up on test referrals, and Medicaid and health departments do little to enforce testing requirements. Additionally, data is often incomplete and surveillance funding and data collection have been cut over the years, so the true scope of the lead exposure problem may not be adequately captured.

Scope of the Lead Problem
Quest Diagnostics (Madison, N.J.) published findings from its Health Trends study online June 10 in the Journal of Pediatrics, in what is believed to be the largest analysis of lead blood level test results in children in the United States.

The study found that based on more than 5 million venous blood lead level results (May 2009 to April 2015), approximately 3.0 percent of children nationally have high blood lead levels (at or above 5 μg/dL). There were significant differences in high blood lead levels based on sex, pre-1950s housing construction quintiles, and poverty income ratio. Health and Human Services regions, states, and 3-digit ZIP code areas also showed “drastically” different frequencies of high blood lead levels and very high blood lead levels (above 10 μg/dL).

Reuters’ analysis similarly found wide geographic variances. For example, across Pennsylvania, 9.4 percent of children tested in 2014 had levels above the 5 μg/dL threshold, while in Cleveland, 13.7 percent of children tested had lead levels above the threshold. For comparison, following the Flint water contamination, 4.9 percent of children exceeded the threshold.

“These alarming findings show that while our nation has made progress in addressing lead exposure, our public health successes are neither complete nor demographically consistent,” said Harvey Kaufman, senior medical director, Quest Diagnostics and a study author. “We have a long way to go, both in terms of contaminated water and residual lead-based paint, to reduce disparities that put some of our children at disproportionate risk of exposure to lead.”

Takeaway: Low levels of lead toxicity screening compliance may be masking a large public health problem of lead exposure in U.S. children.