CDC's Lead and Multielement Proficiency (LAMP) program is a voluntary laboratory standardization program that focuses on whole blood multi-analyte quality assurance. More than 100 laboratories, including 30 international labs, participate in LAMP. Each quarter, these laboratories are required to analyze a CDC-provided set of blood samples and return those results to CDC. CDC provides detailed reports to the labs about how well they performed these analyses. LAMP results are not used for accreditation or certification; however, the program does improve the precision and accuracy of blood lead, cadmium, and mercury measurements. In the future, arsenic and selenium measurements will be added to the program.