The U.S. Food and Drug Administration (FDA) and the U.S. Centers for Disease Control (CDC) recently issued a safety alert that results from some blood tests performed on equipment from Magellan Diagnostics LeadCare Testing Systems failed to detect elevated lead levels in adults and children. A falsely lower result may lead to improper patient care and treatment for lead exposure.
The tests in question are those performed using blood drawn from a vein (also known as venous blood) as opposed to a finger stick or heel prick. Tests performed with Magellan equipment using blood from a finger or heel prick appear to be acceptable results, according to the agencies. Healthcare practitioners' offices generally use blood collected from a heel stick for infants and finger sticks for children and adults for initial lead testing and will usually confirm results using blood drawn from a vein if the initial test result is abnormal.
The alert applies to children and adults who were tested for lead exposure since August 2014. The CDC is recommending retesting for any children under age 6 whose initial lead test was performed on blood from a vein using Magellan equipment and produced a result of less than 10 micrograms per deciliter. Parents with concerns about children older than age six who had the blood tests should speak to their healthcare practitioner about whether retesting is advised. The agency is also recommending that pregnant and nursing mothers who had a venous blood lead test performed using a Magellan Diagnostics' LeadCare analyzer be retested.
Only about ten percent of tests done using Magellan equipment were performed on blood samples from a vein, according to a New York Times report. "While most children likely received an accurate test result, it is important to identify those whose [lead] exposure was missed, or underestimated, so that they can receive proper care," said Patrick Breysse, Ph.D., director of the CDC's National Center for Environmental Health.
Exposure to lead can result in harm to children's developing nerves and brains and lead poisoning poses an increased risk of memory loss and high blood pressure in adulthood, among other health concerns. While those risks have resulted in lead being removed from many products in the last few decades, including gasoline and paint, chipped walls in older homes painted with lead based paints, old toys and some imported toys still pose a risk of lead exposure for children who put the lead-contaminated objects in their mouths, according to the American Academy of Pediatrics.
According to the CDC, about half a million kids in the US ages 1 to 5 currently have blood lead levels above 5 micrograms per deciliter, though the CDC says any level of lead is dangerous. Test results of 10 micrograms per deciliter or higher are an indication for healthcare practitioners to alert public health officials. Health officials then inspect the home and recommend actions to get rid of the lead risks and then do repeat blood tests of lead levels as well as refer for treatment if there is an indication of health concerns.
States have different rules for testing children for lead levels, with some states mandating testing of all children at certain ages and others relying on healthcare practitioners to recommend testing if they think someone is at risk. Healthcare practitioners recommend lead testing for pregnant and nursing mothers if they are concerned about exposure because of the risk of a mother transferring lead to a fetus or young baby.
According to reporting by the New York Times, the flaw in the Magellan equipment may be a substance in the rubber caps of blood tubes used to collect the blood samples that leached into the samples and caused the incorrect results.
"The FDA is deeply concerned by this situation and is warning laboratories and health care professionals that they should not use any Magellan Diagnostics' lead tests with blood drawn from a vein," said Jeffrey Shuren, M.D., director of the FDA's Center for Devices and Radiological Health. "The agency is aggressively investigating this complicated issue to determine the cause of the inaccurate results and working with the CDC and other public health partners to address the problem as quickly as possible."
Until Magellan can resolve this issue, the CDC recommends that venous blood for lead testing be performed using specific testing methods (i.e., inductively coupled plasma mass spectrometry (ICP-MS) or graphite furnace atomic absorption spectrometry (GFAAS)). Finger stick or heel prick samples can be tested by these methods or LeadCare analyzers.