US HITSP: TP21: Query for Existing Data. The Query for Existing Data Transaction Package is based on the IHE Query for Existing Data Integration Profile (QED) which supports dynamic queries for clinical data, including vital signs, problems, medications, immunizations, diagnostic results, procedures and visit history. A wide variety of systems often needs access to dynamic clinical information stored and maintained in an EMR system or other clinical data repository. The construct makes the information widely available to other systems within and across enterprises to support provision of better clinical care.