Some HL7 messages may contain empty (blank) fields. Empty fields in an HL7 message will not overwrite or delete values in existing AutoFill Keyword Sets. Existing Keyword Values are deleted from AutoFill Keyword Sets only if the HL7 field is set to a null value.
Null values in HL7 messages are represented by two single or double quotation marks ('' or ""). If an HL7 field with a null value is mapped to the primary Keyword Type in an AutoFill Keyword Set, the HL7 field is treated as empty, and the primary Keyword Value is not overwritten.