Lead Poisoning Blood Tests May Return Incorrect, Low Readings: FDA

Federal regulators are warning about problems with certain devices used to test the blood for high levels of lead, indicating that they may be providing inaccurate results, potentially leading to children not being properly diagnosed with lead poisoning. 

The U.S. Food and Drug Administration (FDA), along with the U.S. Centers for Disease Control and Prevention (CDC), issued a safety communication on Wednesday, indicating that lead poisoning tests that drew blood from veins may not be accurate. The same problem did not afflict tests which obtained blood from capillary sources, such as in a finger or heel prick.

The warning raises concerns about lead poisoning test results that were negative, which could allow children with high levels of lead in their blood to continue exposure and not receive much needed early intervention, the FDA indicates.

The warning applies to LeadCare Testing Systems by Magellan Diagnostics, Inc., including the LeadCare, LeadCare II, Lead Care Plus and LeadCare Ultra testing systems. They are used in clinics, laboratories, doctor’s offices and hospitals nationwide.

Why the tests are inaccurate for blood drawn from veins, as opposed to blood taken from capillary’s, is unknown at this time.

“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,” Dr. Jeffrey Shuren, director of the FDA’s Center for Devices and Radiological Health, said in a press release. “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.”

The FDA is recommending that health care professionals discontinue using the systems for venous blood samples, but says they can still be used to test blood drawn from capillary sources. The CDC is also recommending that parents of children younger than six, as well as pregnant or nursing mothers, who may be concerned about previous test results, should consult a health care professional about whether to have themselves or their child retested.

Elevated blood lead levels are an indicator that children may be at risk for side effects of lead poisoning, which can cause serious nervous system injury, brain damage, seizures, growth or mental disability, as well as other severe health problems throughout the rest of their childhood and life.

One of the more common causes of of lead poisoning is lead-based paint, which was banned in the United States in 1978 due to the risk of severe and permanent brain damage and developmental problems, particularly in children. However, a number of older homes still contain the toxic paint on the walls, and if it flakes or peals off, young children could ingest the paint chips or breathe dust that comes from the paint, resulting in lead poisoning. Many of those homes are owned by HUD or receive HUD assistance.

In recent years, there has also been an increased focus on lead in drinking water, stemming from the recent and ongoing Flint water crisis, during which a change to the water system in the Michigan city resulted in high levels of lead in residents’ drinking water, causing thousands of children to suffer lead exposure and, potentially, lead poisoning.

The CDC estimates that 535,000 children ages 1-5, or about 2.6% of such children in the U.S., have levels of lead in their blood that place them at risk for adverse health effects. To come up with that number, the CDC analyzed data from the National Health and Nutrition Examination Survey from the years 1999 to 2002, and 2007 through 2010.

The CDC is currently considering dropping its level of concern for lead levels even lower, which could significantly increase that number.

The majority of those children are poor and live in older urban areas, mainly in the inner city. Most are minorities, meaning such exposures add to numerous problems already plaguing inner city black and Latino youths, such as poverty, high crime and poor schools.