Some blood tests used to check for lead poisoning in children and women since 2014 may have wrongly indicated levels that were safe from lead exposure, federal health officials warned. 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. 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. Dr. Jennifer Lowry, chairwoman of the American Academy of Pediatrics’ council on environmental health, 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. 

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

One of the 10 great public health achievements in recent history is the great progress we have made in reducing childhood lead exposure.

Today at least 4 million households have children living in them that are being exposed to high levels of lead. There are approximately half a million U.S. children ages 1-5 with blood lead levels above 5 micrograms per deciliter (µg/dL), the reference level at which CDC recommends public health actions be initiated.

No safe blood lead level in children has been identified. Lead exposure can affect nearly every system in the body. Because lead exposure often occurs with no obvious symptoms, it frequently goes unrecognized. CDC’s Childhood Lead Poisoning Prevention Program is committed to the Healthy People 2020 goals of eliminating blood lead levels ≥ 10 µg/dL and differences in average risk based on race and social class as public health concerns.

Over the past 50 years, EPA and federal and state partners have worked together on actions that have eliminated or drastically reduced the use of lead in gasoline, paint, plumbing pipes, food cans, and a variety of other products. More recently, EPA has cleaned up lead-contaminated waste sites and established standards for dealing with lead-based paint that was used in the previous century. In addition, the public health and medical communities have worked together to increase awareness, identify populations at risk, and provide blood lead testing for communities. As a result of these collective actions, blood lead levels have declined by more than 90% since the mid-1970s.