The institutions noted that the problem could go as far back as 2014.
Federal officials are warning that some blood tests may have "significantly" underestimated lead levels, and they are urging the retesting of some children, as well as pregnant and breast-feeding women.
The FDA says certain lead tests may be faulty.
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 USA - should be accurate.
Healthcare professionals and public health laboratories should discontinue using Magellan's LeadCare System Testing System with venous blood samples, due to concerns about inaccurately low results, said the FDA in a safety communication. At this time, all LeadCare systems can be used with blood from a finger or heel stick, including the LeadCare II system - a system found in many doctors' offices and clinics.
Shuren added that "the agency is aggressively investigating this complicated issue to determine the cause of the inaccurate results and working with the CDC [Centers for Disease Control and Prevention] and other public health partners to address the problem as quickly as possible".
Lead testing in children is typically done by a finger or heel stick known as capillary test. Meridian Biosciences acquired Magellan in 2016.
Since 2014, 9,363 children under the age of six had tests performed with LeadCare equipment using venous blood samples, which is 1.7 percent of all the blood lead tests performed during that time.
"Children are particularly vulnerable to lead exposure due to the effect on their developing brains and organ systems", the Centers for Disease Control and Prevention said.
The FDA's warning was issued for all four lead testing systems from Magellan Diagnostics including LeadCare, LeadCare II, LeadCare Plus and LeadCare Ultra.
Apart from children, CDC also advises pregnant and nursing women to undergo another lead test if their blood was drawn from the veins.
The CDC warns that "no safe blood lead level in children has been identified".
"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.
Asked why taxpayers or insurance companies should have to pay for retesting, Hill said the first priority is to get kids retested if they need retesting, and officials do not want reimbursement to hold that up. Infants and young children are especially vulnerable to the effects of lead poisoning, which can cause cognitive deficits and affect nearly every system in the body. "It's important to remember that lead does not stay in the blood for very long, so a low test result today may not tell you if there was past exposure". Children in at least 4 million households are exposed to high lead levels, according to the CDC.