On May 17, the Food and Drug Administration (FDA) issued a warning that Magellan Diagnostics’ LeadCare tests might underestimate blood lead levels when performed on venous blood samples. To determine the cause of these inaccurate results, the agency launched an investigation that involved an inspection of Magellan Diagnostics’ facility in North Billerica, Massachusetts. This inspection uncovered several issues that may be violations of federal law. These issues include design validation that failed to ensure LeadCare systems conform to defined user needs; failure to identify and adequately evaluate the risk to patients posed by falsely low test results obtained on these systems; and failure to report in a timely manner user complaints indicating that the LeadCare Ultra system had experienced a malfunction that could contribute to a death or serious injury. FDA is now reviewing the evidence collected during the inspection to determine if further action is warranted.