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

Code Display Definition
stat Immediate Immediately in real time.
normal Normal With best effort.
deferred Deferred Later, 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>