Hi I didn't find a category discussing mapping questions , please point me in the right direction if any . I need your help please to understand some basic principle . I’m looking into MessageHeader part of ADT_A01 to Bundle mapping . http://hl7.org/fhir/uv/v2mappings/2020Sep/ConceptMap-segment-msh-to-messageheader.html There are many places where the target field is reference . For instance , from MSH-4 to [MessageHeader.sender]. If I’m not mistaken that means that value from MSH-4 is copied to entry/resource/MessageHeader/sender/reference/@value. But how come HL7 Sending Facility value can serve as a reference from one FHIR resource to another ?

Hi , Can anyone please suggest where I can download negative test data, i.e. resource data fails on validation. Specifically I need patient data ( not bundle) Thanks