New York Times: F.D.A. Warns of Faulty Lead Testing in Children and Mothers

Some blood tests used to check for lead poisoning in children and women since 2014 may have wrongly indicated that children were safe from lead exposure, federal health officials warned Wednesday. Children under 6 and pregnant and nursing women may need to be retested.

The concern is that the original tests may have underestimated blood lead levels, providing false assurance to parents. Infants and young children are especially vulnerable to the effects of lead poisoning, which can cause cognitive deficits and affect almost every system in the body.

The tests under scrutiny are made by Magellan Diagnostics, which discovered as far back as 2014 that its three-minute test, conducted in a doctor’s office, could yield inaccurate results when used on blood drawn from a vein, Food and Drug Administration officials said in a news conference. Most lead tests in children are taken by pricking the finger or heel to draw samples of capillary blood for testing. The F.D.A. said there was no evidence at this point that the finger- and heel-pricking methods have provided inaccurate results, and for reasons that still aren’t clear, only venous blood has been associated with an inaccurate reading.

F.D.A. officials estimate that eight million tests have been run using the Magellan system since 2014, but said the majority were done using capillary blood, not blood drawn from the vein. Meridian Biosciences, which last year acquired Magellan, which is based in Billerica, Mass., issued a statement noting that venous blood testing accounts for about 10 percent, or about $1.8 million, of Magellan’s revenue.

“Meridian and Magellan take these matters very seriously and will continue to work closely and fully with the F.D.A. and C.D.C. to address the concerns identified with venous samples as quickly as possible,” the statement said.

Dr. Jennifer Lowry, chairwoman of the American Academy of Pediatrics’ council on environmental health and section chief for toxicology and environmental health at Children’s Mercy, said that most pediatricians draw blood from the vein only if the lead level from a finger- or heel-stick is elevated and they want to confirm the result. She said most doctors would send the confirmatory venous blood sample out of the office for analysis by a different testing system. She said that while the overall number of people affected may not be large, it’s a problem for those who had a normal test result that was an error.

The F.D.A. emphasized that it has just started its investigation.

Health officials urged retesting of children under 6 who had blood drawn from a vein for a lead test done using Magellan Diagnostics LeadCare systems and whose test result was less than 10 micrograms/deciliter. Pregnant and breast-feeding women with similar test results and circumstances should also be retested, officials said.

Lead is so toxic that no blood lead level is considered safe, but levels of 5 micrograms per deciliter or more set off alarms for health care providers, who then try to identify where the child has been exposed to lead at home or school and take steps to reduce exposure. Children with high lead levels receive repeat blood tests at frequent intervals. The concern is that an inaccurate result could have wrongly reassured parents, and prevented them from taking steps to protect the child from additional exposure.

Read the full article via the New York Times.

Hear more from Dr. Lowry on lead poisoning, Long-lasting effects, Changing your child's diet.