The recommendation from the CDC recognizes what doctors have long believed: that any amount of lead can be harmful. And they expressed satisfaction that the level was lowered.
"Going backward can be really hard, and for doctors with paper charts it could be near impossible," said Dr. Scott Krugman, chairman of the MedStar Franklin Square Medical Center's department of pediatrics. "And even for those of us with electronic records, the guidance isn't clear about how far we should go back."
He said lead is a concern for children through age 5, so doctors will need to consider looking at records for all in that age range. They are typically tested for lead at ages 1 and 2, and retested in three to six months if there are abnormal levels, said Krugman, also the vice president of the Maryland Chapter of the American Academy of Pediatrics.
His clinic has 12,000 young patients, many who live in high-risk areas because housing stock is older and may contain lead-based paint. The CDC's "level of concern" since 1991 had 10 micrograms per deciliter of lead in a child's blood. The new level effectively becomes 5 micrograms per deciliter but may fluctuate over time with the population.
Those in that new level between 5 and 10 will be retested to ensure the levels have dropped. Those whose levels remain elevated will be treated and referred to local health departments, which provide home visits and tips or removal of lead-based hazards.
"By [age] 6 you would expect the levels to go down because kids stop putting everything in their mouths," he said about lead sources such as paint chips, some imported jewelry and dirt. "Rarely do we see them go up, unless there is a significant renovation or some other factor."
Years ago, doctors would see children with levels above 60 and they would likely have "very dramatic confusion," said Dr. Catherine Parrish, senior pediatrician at Johns Hopkins Community Physicians in Canton Crossing.
But sometimes, doctors still see children above level 20, which could mean lower IQs and developmental delays. They may be treated with chelation therapy, an oral medication used to remove heavy metals from the body. Treatment for those with levels of 5 to 20 typically involves a vitamin with iron to absorb the lead. Those children might also have developmental delays, but it would be hard for doctors to pin those problems exclusively to lead exposure, Parrish said.
Her practice sees about 6,000 children, and Parrish didn't expect to find a large number of new cases to address. And like Krugman, she expected most would have reduced levels from their baseline tests.
Cases have been dropping in general in Maryland — 98 percent since the mid-1990s, when a state law began requiring landlords of pre-1950s housing to repair and clean units to reduce the risks.
"I've been doing this for 26 years, and the number of children with lead exposure will be far fewer than it would have been even 10 years ago because of the aggressive screening," Parrish said. "The unfortunate thing is now we have far fewer places to go and people to help us look at the houses these kids are living in."
In Baltimore, where the incidence of poisoning is eight times that of the rest of the country, the Health Department is trying to stretch resources, said Health Commissioner Oxiris Barbot.
She wasn't sure how many children will be added to the rolls once local pediatricians review their cases but said the department anticipated the CDC recommendation and began months ago visiting households with children with the lower levels already in their records. About 270 families have been contacted and offered home visits and tips to reduce exposure.
The health and housing departments also have partnered to stretch dollars. Housing officials, who do remediation work in public housing, can identify lead problems when they are in the homes for other reasons, Barbot said.
But she said the money for lead programs has been scaled back drastically, possibly hampering efforts just when there is likely to be an increase in home visits needed.
The city Health Department got $300,000 this year from the CDC to track exposure and poisoning cases and help families reduce lead in the home. But the money runs out in September because Congress cut the CDC lead program budget from $29 million to $2 million.
Barbot said the department will determine priorities once it has a clear picture of new cases. It will be a "tricky" balance because some children have moved and may have new exposures, and others are old enough that lead should no longer have an impact.