Merge Item documents can use default values mapped to HL7 fields as Keyword Values. To apply default values, you must both map a Keyword Type and assign a default value to an HL7 field. If the field has a value in an incoming HL7 message, the value in the field is used as the Keyword Value. If the field doesn't have a value, the field's default value is used as the Keyword Value. To map Keyword Types and assign default values to HL7 fields, see Configuring Message Templates.