This class links two Clinical Information records that are related to each other in some way. This class is intended to only link two records of the same type together. For example, to link an Order with another Order, or an Observation with another Observation. Relationships between different kinds (i.e., different subtypes) should be modeled explicitly. In general, there are two reasons why a Clinical Information record is related to another Clinical Information record: a) if one record is replacing another; or b) if one record has subordinate record(s) (often called a “parent/child” relationship). The relatedInformationCategory property indicates how the referenced Clinical Information record is related to the "owning" Clinical Information record. This construct allows the relationship to be traversed in either direction: for example, the “parent” record could point to its “children” records, or the “children” records could each point to their “parent”, or both could be the case. Thus the vocabulary for the relatedInformationCategory code will contain entries for either directionality, that is: “parent”, “child”, “replaces”, and “replaced by”. For example, say that Order1 and Order2 are instances of Order, and that Order2 is replacing Order1. Then: a1) Order1. relatedClinicalInformation. relatedInformationCategory is set to (a code that means) "replaced by" and a2) Order1. relatedClinicalInformation. clinicalInformation points to Order2, and/or: b1) Order2. relatedClinicalInformation. relatedInformationCategory is set to (a code that means) "replaces", and b2) Order2. relatedClinicalInformation. clinicalInformation points to Order1. "Relates a child to its parent when a parent child relationship exists." - HL7 Version 2, ORC-8. "This field is defined to make it available for other types of linkages (e.g., toxicology). This important information, together with the information in OBR-29 or OBR-57, uniquely identifies the parent result's OBX segment related to this order." - HL7 Version 2, OBX-26. "Completed or terminated request(s) whose function is taken by this new [Request sub-type]." - HL7 FHIR, Request.replaces pattern. Note that in Laboratory, a "Reflex Test" will be handled through this RelatedClinicalInformation mechanism. A Reflex Test is a test that is performed and is made necessary based on results from another test, such as results that need confirmation or tests that are indicated by standards of care, so that it is necessary to perform even though the clinician hasn't ordered it. Examples include when a CBC indicates a high white blood cell count, a differential is automatically performed. These tests are usually defined within the laboratory's established procedures. In this example, the original order will point to an instance of RelatedClinicalInformation, wherein the relatedInformationCategory will contain a code that means "reflex test", and a pointer (i.e., the clinicalInformation property) that points to the reflex test promise. Similarly, the reflex test promise can point to another instance of RelatedClinicalInformation, wherein the relatedInformationCategory will contain a code that means "original promise", and a pointer (i.e., the clinicalInformation property) that points to the original lab test promise.