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Delimiter Escape Sequences

If an HL7 message contains one of the special delimiter characters as part of its message content, you can use a special escape sequence to specify the delimiter character. This ensures that any application that processes HL7 messages can always distinguish between a delimiter character and a character that is part of the message text.

Each delimiter character has its own escape sequence. This escape sequence consists of the \ character followed by a unique capital letter, followed by \. The following table lists the delimiter characters and their equivalent escape sequences:

Character	Escape Sequence
&	\T\
^	\S\
|	\F\
~	\R\
\	\E\
Hexadecimal character xx	\Xxx..\

In the \Xxx\ escape sequence, xx is a two-digit hexadecimal number representing the ASCII value of a character.

Note that the \ escape character has its own escape sequence.

In addition to the above escape sequences, some additional special escape sequences are defined. These escape sequences are left unchanged.

Sequence/Type	Format
Highlighting Sequences	\H\ \N\
Formatting Sequences (starting with a period)	\.br\ \.fi\ \.nf\ \.sp\ \.in\ \.ti\ \.sk\ \.ce\
Character Set Codes	\Cxxyy\ (single-byte) \Mxxyy\, \Mxxyyzz\ (multi-byte)

These escape sequences enable you to include formatting information as part of a segment composite.