 Many software vendors use EMPI and MPI (master patient index) synonymously, because an MPI is only workable if it is used by all software applications across an entire enterprise; that is, "master" implies enterprise-wide scope.EMPIs use match engines along with the technique of referential matching to more easily identify duplicate patient records.In computing, an enterprise[-wide] master patient index is a form of customer data integration (CDI) specific to the healthcare industry.