This code system http://terminology.hl7.org/CodeSystem/processpriority defines the following codes:

CodeDisplayDefinition
stat ImmediateImmediately in real time.
normal NormalWith best effort.
deferred DeferredLater, when possible.
<status value="draft"/><experimental value="false"/><description value="This value set includes the financial processing priority codes."/><copyright value="This is an example set."/><caseSensitive value="true"/><content value="complete"/><concept><code value="stat"/><display value="Immediate"/><definition value="Immediately in real time."/></concept><concept><code value="normal"/><display value="Normal"/><definition value="With best effort."/></concept><concept><code value="deferred"/><display value="Deferred"/><definition value="Later, when possible."/></concept></CodeSystem>