HL7 resources

HL7 Escape Sequences

HL7 defines character sequences to represent ’special’ characters not otherwise permitted in HL7 messages. These sequences begin and end with the message’s Escape character (usually ‘’), and contain an identifying character, followed by 0 or more characters. The most common use of HL7 escape sequences is to escape the HL7 defined delimiter characters.

CharacterDescription Conversion
CxxyySingle-byte character set escape sequence with two hexadecimal values not converted
EEscape character converted to escape character (e.g., ‘’)
FField separator converted to field separator character (e.g., ‘|’)
HStart highlighting not converted
MxxyyzzMulti-byte character set escape sequence with two or three hexadecimal values (zz is optional) not converted
NNormal text (end highlighting) not converted
RRepetition separator converted to repetition separator character (e.g., ‘~’)
SComponent separator converted to component separator character (e.g., ‘^’)
TSubcomponent separator converted to subcomponent separator character (e.g., ‘&’)
Xdd…Hexadecimal data (dd must be hexadecimal characters) converted to the characters identified by each pair of digits
Zdd…Locally defined escape sequence not converted

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