The Act.priorityCode is defined by HL7 as “a code or set of codes (e.g., for routine, emergency), specifying the urgency under which the Act happened, can happen, is happening, is intended to happen, or is requested/demanded to happen.”
The semantics of this attribute potentially overlaps with SNOMED CT “[ 260870009 | priority ]” attribute which "... refers to the priority assigned to a procedure".
The following rules recommend specific uses for the HL7 and SNOMED CT representations of priority. There are two sections dealing with information models which 1) contain SNOMED content and 2) allow multiple terminologies to be used.
In all cases:
- Act class clones SHALL include the priorityCode attribute if there is a requirement for expressing the urgency of a request, tracking and auditing services based on requested prioritization or any other aspects of workflow management related to priority.
- Act class clones need not include the priorityCode attribute if the only requirement for indicating priority relates to distinguishing differences between the nature of the procedure itself based on priority (see example below).
- In Act class instances the Act.priorityCode attribute SHALL be used where it has a specific functional role in relation to the purpose of a communication.
- For example, to prioritize a request for a service or to track the priority under which a service was scheduled and carried out.
In cases where SNOMD-CT is used.:
- In Act class instances, the relevant SNOMED CT priority attribute SHOULD be included in the expression in the Act.code or Observation.value if the priority significantly alters the nature of the statement.
- The priorityCode SHALL be the same as, or a subtype of, the value of the relevant priority attribute as specified in the SNOMED-CT expression
- For example, an [ 274130007 | emergency cesarean section ] is a significantly different procedure when compared with an [ 177141003 | elective caesarean delivery ].
At face value the Act.priorityCode and the SNOMED CT [ 260870009 | priority ] attribute appear to have similar meanings. However, the way in which these are used appears to differ significantly. These aspects of priority can vary independently of one another. Two requests for the same procedure can assert different priorities for processing them based on perceived clinical need or other factors. On the other hand, some emergency procedures are carried out directly without a specific request and thus without the normal workflow associated with prioritization.
- The SNOMED CT attribute is used to specify the defining characteristic that distinguishes an elective procedure from an emergency procedure. Like any defining attribute it can also be used to refine or qualify a procedure that is specified without references to its urgency.
- The HL7 priorityCode is generally used to communicate priority in relation to workflow management and audit. One obvious use case for this is to allow request for a service to indicate the priority assigned to it by the requester.
The use of a distinct information model attribute (i.e. Act.priorityCode), which is applicable to all services, makes the priority more readily accessible to workflow management. It does not require the SNOMED CT expression to be parsed to determine the priority of a request or action. In addition, it allows consistent handling of priority when some services are represented using SNOMED CT while others are represented using different code systems.
The use of a representation of priority that is integrated with the definition model of the associated concept is more useful from the perspective of clinical record retrieval. The description logic model of SNOMED CT ensures the computational equivalence of a procedure concept defined as an emergency and a post-coordinated expression in which [ 260870009 | priority | = 25876001 | emergency ] is added to the more general procedure concept.