New York (Reuters) - Los Angeles County overstated the number of local children with elevated lead tests in recent years, internal emails show, making it harder to track the public health burden of lead exposure in one of the country’s most densely populated areas.
The error occurred when officials at the Los Angeles County Department of Public Health mistakenly categorized some blood lead test results as “elevated” in health data shared with Reuters. Negative test results from one major laboratory were miscounted as elevated results for the years 2011 to 2015.
As a consequence, the countywide lead testing data released to Reuters misstated the number of children with an elevated lead test in some L.A.-area neighborhoods. Children who test high warrant a public health response, according to federal health watchdog the U.S. Centers for Disease Control and Prevention.
How many results were misstated remains unclear, but the error may come as a relief to communities such as San Marino, an affluent area where the data overstated the prevalence of high tests.
The countywide lead testing results were originally released to Reuters on March 30 in response to a records request. They were part of a story the news agency published on April 20 examining the burden of lead exposure on children in the L.A. area.
The data showed many neighborhood areas where a high rate of children tested for lead had elevated results. That stoked concern among residents in places like San Marino, just south of Pasadena.
The county had reported that 17 percent of tests from one San Marino census tract were elevated, at or above the CDC threshold. The correct figure was closer to 1 percent, the county later determined.
The error occurred because of a misinterpretation of lab results. County health officials counted negative tests from one laboratory – at the Children’s Hospital Los Angeles – as elevated, or 5 micrograms per deciliter. In reality, the laboratory had merely reported that these tests came back below its detection limit. They didn’t qualify as elevated.
So far, the county health department has only corrected its error for results in San Marino. Instead of 28 children testing high for lead in San Marino’s western census tract, as the county data had shown, just 2 kids tested high, it said.
But the data errors likely extend beyond San Marino, Reuters has confirmed. Children’s Hospital Los Angeles said it conducted around 5,000 childhood blood lead level tests from 2011 through 2015. All of these tests may have been counted as high. That could mean that almost a third of the 15,000 L.A. County children counted as receiving a high test did not have one.
The correct results across the county of 10 million residents remain unclear. County health officials declined to restate data for the 1,547 other census tracts covered in the department’s earlier data release.
Public health specialists said the lack of disclosure could create confusion. They also cautioned that lead poisoning risks, from old paint to tainted soil, remain significant in many L.A. areas. For every California child found with a high lead level, approximately two are never diagnosed, according to a study published in the journal Pediatrics in April.
No level of exposure is considered safe. Lead hampers childhood development, and can lead to lifelong health impacts.
Yet California requires testing for only a small portion of children. “Under-testing appears to be a huge problem,” said Dr. Eric Roberts, the lead author of the Pediatrics article, and a researcher at the Public Health Institute’s California Environmental Health Tracking Program.
After receiving the original blood testing data for L.A. in March, Reuters sought out county officials to understand why some rates were so high. For San Marino, they cited factors including older housing containing lead paint, along with imported pottery and foodstuffs from China that could contain lead.
Once Reuters had published its report, health officials – under pressure from leaders and residents in San Marino – offered a different explanation. On or around April 26, county health officials discovered they had misstated the number of children who tested high in San Marino, internal county emails obtained by Reuters show. They updated the community at a public meeting that week.
At the meeting, the county’s toxicologist, Dr. Cyrus Rangan, attributed the error of interpretation to Reuters, inaccurately saying the news agency never checked the data with the county before publishing. In a phone interview, Rangan apologized for his misstatement.
The laboratory whose results were misinterpreted said it had followed state reporting guidelines.
“We were not aware of how the county or state were recording these levels,” said Maurice O’Gorman, chief of laboratory medicine at Children’s Hospital Los Angeles.
The data problems are unlikely to recur. That’s because in late 2015, the laboratory lowered its detection limit for lead test reporting from 5 to 2 micrograms per deciliter, providing greater precision.
In San Marino, an area where many old homes contain lead paint, officials said they are still committed to new measures to limit exposure risks.
The city is developing an ordinance that would require contractors who engage in renovation, repair or painting to be certified in lead safe-work practices prior to receiving a city permit or business license. Contractors would also have to provide documentation confirming that lead found during their work was properly abated.
City staff planned to conduct lead tests of all drinking fountains and sinks in all city facilities and will test for lead at schools and city centers.
“We’re not saying ‘OK, we’re all fine,’ ” said Cindy Collins, San Marino interim city manager. “Now there’s an awareness for us.”
The earlier data made public by the county showed the number of children in each of 1,548 census tract areas across L.A. County who were tested for lead exposure from 2011 to 2015, and the number who received at least one elevated test – meeting or surpassing the CDC threshold.
In response to Reuters questions about the data errors, the county health department issued a statement calling elevated blood lead tests “a major concern” for public health since no exposure level is safe. Determining the burden of lead poisoning in any community requires appropriate analysis, it added.