It’s easier than ever for parents (and parents-to-be) to get their lead levels tested, but federal officials are now warning American families that certain popular lead tests may provide inaccurate results, increasing the risk for lead poisoning in certain young children and adults.

The U.S. Food and Drug Administration and the Centers for Disease Control and Prevention are sounding the alarm to warn parents of children who are six years or younger, nursing or expectant mothers, and the elderly that certain lead tests manufactured by Magellan Diagnostics — widely used by many doctors and laboratories around the country — may show that lead levels in the blood are lower than they actually are.

If you fall into any of those categories, the CDC recommends you talk to your doctor or another healthcare professional about whether or not you should be retested.

“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.”

The warning includes all four of Magellan Diagnostics’ lead testing systems: LeadCare; LeadCare II; LeadCare Plus; and LeadCare Ultra.

The FDA believes the issue may date back to 2014, when Magellan first received complaints from customers. At the time, the company considered the issue resolved, but during a diagnostic review of the company’s 510(k) clearance paperwork, the FDA started to ask more questions and disovered that Magellan had “significantly” underestimated the amount of risk to the public.

Officials found that the company didn’t have adequate data and documentation regarding the cause of the problem and their mitigation efforts, Dr. Shuren noted.

Though Magellan had identified another inaccuracy issue with an additional product in 2015, that information was not conveyed to the FDA during the 510(k) process despite repeated interactions, Dr. Shuren said, because the company saw it as a low-risk issue it considered resolved.

“This would have been for us a material fact,” Dr. Shuren says, and is also “one of the aspects of our active investigation.”

Health officials finally discovered there could be a problem in March this year, during the review of a 510(k) pre-market submission.

Dr. Shuren says inspectors are on-site at Magellan in an effort to figure out how this happened, telling reporters on a conference call today that the cause of the misreading might not be something specific to the test, but could be due to other tubes like the tubes where the specimens are collected, or reactions with chemicals involved.

At this time, any of those tests performed with blood drawn from a finger or heel stick — which is how most lead tests are conducted in the U.S. — should be accurate. Because this method is widely used, most people will likely not be affected by inaccurate tests, officials say. There are also other blood tests doctors and labs may use that are not Magellan, and those are not affected.

Officials say they understand that people affected by this issue are going to be concerned about their health, and note that while most children likely received an accurate test result, it is important to identify any whose exposure may have been missed or underestimated.

“For this reason, because every child’s health is important, the CDC recommends that those at greatest risk be retested,” said Patrick Breysse, Ph.D., director of the CDC’s National Center for Environmental Health.

Lead exposure is dangerous: It can affect almost every system in the body while producing no obvious symptoms, and as such, often goes unrecognized. Lead poisoning is particularly dangerous for infants and young children. To that end, all states lead screening for children.

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