The Food and Drug Administration is recommending repeat lead testing of young children and at-risk women who were tested via a venous blood sample. The recommendation was issued May 17 after the agency discovered a probable 3-year history of inaccurate tests by the nation’s largest lead test distributor.

The tests should be repeated with a capillary sample in children younger than 6 years of age as of May 17, and all pregnant or breastfeeding women who had a lead level of 10 mcg/dL or lower in a venous blood draw tested with any system made by Magellan Diagnostics, FDA representatives said during at a press briefing.

Tests run since 2014 that used capillary blood obtained by finger or heel stick are accurate and do not need to be repeated, according to Jeffrey E. Shuren, MD.

“We do have evidence of a problem with falsely lower lead reading with venous blood,” said Dr. Shuren, director of the FDA Center for Devices and Radiological Health. “Based on the information we have now, we don’t know how often we see this inaccuracy in samples, or how much lower it is. There is a wide variation and a small amount of data. We need to do further testing to see how big the problem is and the root cause. However, we do have enough data to be confident that we don’t have the problem in capillary blood.”

The warning includes all tests run on four of Magellan Diagnostics’ lead testing systems: LeadCare; LeadCare II; LeadCare Plus; and LeadCare Ultra. All LeadCare systems can be used with blood from a finger or heel stick, including the LeadCare II system – one found in many doctors’ offices and clinics. In addition, some laboratories offer other methods of lead testing, which are not now believed to be affected.

At this point, Magellan isn’t required to pay for any retesting. Tim Hill, acting director of the Center for Medicaid and CHIP Services, who was also on the call, confirmed that retesting will be covered for Medicaid and CHIP recipients. Patients with private insurance will have to contact their insurance companies to ascertain coverage, he said.

“Our first priority is to be sure folks get retested through our programs,” Mr. Hill said during the briefing. “We don’t want reimbursement to hold up the retesting. My understanding is that talks with Magellan with regard to their liability are ongoing.”

Regulators discovered the extent of the problem in March, after Magellan submitted a 510(k) premarket notification for a new iteration of its point-of-care test, FDA spokesperson Tara Goodin said in an interview. The new product was based on a kit approved in 2013, so all tests run on venous blood since then are in question.

During the data review, FDA discovered that customers began complaining to Magellan about inaccurate results on venous blood in 2014. Magellan issued three customer notifications letters (primarily to laboratories) alerting them to testing inaccuracies and recommending mitigations designed to address them. These customer notifications were issued on Nov. 24, 2014; Nov. 4, 2016; and April 28, 2017. In these, the company indicated that about 2.5% of patients whose tests were below the level of medical concern could actually have enough lead to warrant intervention. Magellan suggested that the problem could be solved by holding all samples for 24 hours before mixing them with the reagent – a step the company said would reduce risk of a misread to zero.

Regulators disagreed, Ms. Goodin said.

“Based on available information, the FDA believes that Magellan should have determined that the risk of an inaccurate test result and the number of people that could be adversely affected was much higher than they estimated and that their mitigation might not be adequate to address the increased risk. Instead, the company submitted a malfunction report in 2015 related to an observed increased frequency of falsely low test results in the LeadCare Ultra system that the firm indicated it first identified through the August 2014 complaint.”

In the malfunction report , the company characterized this issue as a Class III recall, which the FDA defines as a situation in which use of or exposure to a violative product is not likely to cause adverse health consequences.

The scope of the problem became apparent only after Magellan submitted its 510(k) paperwork in March, Ms. Goodin said.

“After reviewing initial data available from Magellan on these inaccuracies and their mitigations, the FDA was unable to identify the root cause of the inaccuracies, the frequency and extent of the inaccuracies, or to confirm that the mitigations are effective. While the FDA’s investigation is in its early stages, we did not want to delay warning health care professionals and laboratories about the risk of testing inaccuracies and encouraging parents and at-risk adults to follow the CDC’s recommendations.”

As soon as FDA identified the issue as a potential public health risk, it began working with the Centers for Medicare & Medicaid Services to issue recommendations for laboratories, health care professionals, and at-risk individuals.

“The FDA prioritized communicating to the public about this issue but is also aggressively investigating this issue to determine the cause of the inaccurate results and will provide updates as more is learned,” Ms. Goodin said. “This includes reviewing data provided by the company, requesting additional information from Magellan regarding the issue, and inspecting the company’s facility. The FDA has also requested an independent analysis of the test. We are aggressively investigating this issue and have already sent staff to inspect Magellan’s facility.”

Phone calls to Magellan for clarification on its mitigation procedures, the potential impact on customers, and the history of the LeadCare series’ approvals were not returned at press time, and the company had no prepared statement. A safety communication was posted to its website.

Since 2014, Magellan has run 8 million blood lead tests. Based on the company’s 2.5% estimate of misreads, 200,000 patients tested with the kit could have dangerously high blood lead levels. Currently, the FDA has no official estimate of how many tests were run on venous blood, how many of those returned inaccurate results, or even what caused the tests to read out with falsely low levels, Dr. Shuren said.

“We are investigating the cause, however when [Magellan’s prior test kits] came on the market, there was data supporting their accuracy. The root cause of this, we don’t know. It may not be specific to the test; it may have to do with the tubes, the reactions with chemicals, the way it’s processed. We are looking into all [of] these.”

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