Unless the lab has specified a different character set in the MSH segment, this should be reported to them as a bug. Default HL7 does not allow non-printable characters in the data. From the HL7 encoding rules in section 1.6.1 of version 2.31:
All data is represented as displayable characters from a selected character set. The ASCII displayable
character set (hexadecimal values between 20 and 7E, inclusive) is the default character set unless
modified in the MSH header segment. The field separator is required to be chosen from the ASCII
displayable character set. All the other special separators and other special characters are also displayable
characters, except that the segment separator is the ASCII Carriage Return character.
It's one of my pet peeves with reference labs in particular. As a lab vendor, I take a lot of pains to make sure the data we send in HL7 is both compliant and useable. Too many these days expect other systems to magically use the same character font and kerning so their highly formatted canned text will display/print properly.