The Percentilerproject provides quasi real-time access to patient medians across laboratories and manufacturers. This data can serve as “clearinghouse” for electronic health record applications, e.g., use of laboratory data for global health-care research. Methods:Participants send their daily outpatient medians to the Percentiler application. After 6 to 8 weeks, the laboratory receives its login information, which gives access to the user interface. Data is assessed by peer group, i.e., 10 or more laboratories using the same test system. Participation is free of charge. Results:Participation is global with, to date, > 120 laboratories and > 250 instruments. Up to now, several reports have been produced that address i) the general features of the project ii) peer group observations; iii) synergisms between “The Percentiler” and dedicated external quality assessment surveys. Reasons for long-term instability and bias (calibration- or lot-effects) have been observed for the individual laboratory and manufacturers. “The Percentiler” project has the potential to build a continuous, global evidence base on in vitro diagnostic test comparability and stability. As such, it may be beneficial for all stakeholders and, in particular, the patient. The medical laboratory is empowered for contributing to the development, implementation, and management of global health-care policies.

Quality, indicator Median Moving, median Stability of performance Shifts, laboratories.