The commenter suggestions are interpreted as a desire for US Core to to support or promote system level search which is currently out of scope.  The US Core Implementation Guide is based on FHIR Version R4 and defines the resources needed for the US Core Data for Interoperability and the  minimum  conformance requirements for accessing patient data which is defined for single patient data. Quering for >1 patient level data id discussed in the futures sectiond. (The Argonaut team have discussed at length how to support multiple patient queries and the conensus was that implementers should reference the bulk data specification for those interactions).  http://build.fhir.org/ig/HL7/US-Core/future-of-US-core.html#future-candidate-requirements-under-consideration Other specification such as Bulk Data ( https://hl7.org/fhir/uv/bulkdata/#us-core-data-for-interoperability ) use US Core profile to access system level data. . US Core Profiles are appropriate for use by Public Health Reporting use cases and the Implementation guide for a portion of Public Health Reporting use cases. Will add guidance that conformance to a US Core profile, and conformance to the US Core IG are different. One is a structural conformance to the resources as profiled by US Core, the other is US Core profiles + interaction for the use case So you can export all resources needed for the US Interoperability, as profiled by US Core, but not claim conformance to the the IG. In fact Bulk data does this. The conformance statements list only those search parameters needed to compose the search parameter combinations, because these parameters have documentation around usage when used in alone and in combination.  The MAY expectations are not intended to be exhaustive of all possible search parameters or interactions. Will add a note to the CapabliltyStatement narrative to clarify.  ADD - guidance - for population-level queries for public health surveillance such as all patients with COVID diagnosis point readers to Bulk Data with pointer to bulk architecture.