Shipped with Chameleon versions 5.0 and later, the GUID (Globally Unique Identifier) Generator allows you to create unique IDs for use with HL7 messages, with the most common use associated with message control IDs (MSH.10).

The generated GUID is a sequence of bits represented by a hex-encoded string. The length of this sequence of bits must be at least 128, and must be divisible by 8.

The number of characters in the string equals the number of bits in the GUID divided by four. Therefore, a 128-bit GUID is represented as a 32-character string, and a 256-bit GUID is represented by 64 characters.