The U.S. Food and Drug Administration said it continues to recommend that Magellan Diagnostics Inc.'s lead detection tests not be used with blood samples taken from the vein.
In May 2017, the FDA and the Centers for Disease Control and Prevention warned that the LeadCare tests manufactured by Meridian Bioscience Inc., which were used to detect lead exposure, could provide false results in some children and adults.
Later in October 2017, the regulator issued a warning letter to Magellan Diagnostics for federal law violations involving its blood lead-testing systems after it found that the company sold modified versions of its two blood lead-testing systems without FDA approval.
The FDA issued a warning letter to Becton Dickinson and Co. in January for selling significantly modified and unapproved versions of its BD Vacutainer blood collection tubes and failing to submit medical device reports to the FDA within the required time frame. The violations were flagged by the FDA after inspecting Becton Dickinson's Franklin Lakes, N.J., facility as part of a larger investigation into Magellan Diagnostics' blood tests.
The agency said that after the May 2017 warning, it engaged Becton Dickinson to determine the cause of the inaccurate results. Becton Dickinson is the manufacturer of certain blood sample collection tubes often used alongside many lead tests.
At the FDA's request, Becton Dickinson conducted studies to assess the accuracy of the LeadCare testing systems when used with blood from the vein collected into Becton Dickinson tubes.
Becton Dickinson found that the rubber stoppers in the affected tubes contained a chemical called thiuram, which can release sulfur-containing gases that dissolve into blood samples and bind tightly to lead particles. This reaction makes it difficult for the lead tests to detect the correct amount of lead in a sample.
The recommendation not to use Magellan lead tests with blood samples taken from the vein applies to all brands of collection tubes used for blood drawn from the vein as thiuram may be used to manufacture rubber stoppers by other blood collection tube manufacturers, the agency stated.
The FDA is following up with blood collection tube manufacturers serving the U.S. market to investigate if this issue may impact collection tubes marketed by companies other than Becton Dickinson and is evaluating other factors that may have contributed to inaccurate results observed with the Magellan lead tests.
Becton Dickinson is also conducting testing to determine whether clinical laboratory tests other than the Magellan lead tests are affected by thiuram but the FDA does not believe there is currently evidence showing that other tests are impacted by the chemical interference.
The FDA also has no evidence at this time that other methods of measuring blood lead, including mass spectrometry or atomic absorption method lead tests, are affected by the interference.
Magellan's lead test systems can continue to be used with blood samples from a finger or heel stick, according to the FDA.
The FDA said it is working with the U.S. Centers for Disease Control and Prevention on an independent analysis of Magellan Diagnostics' LeadCare system tests.