In working with record administrators, they will often run algorithms on their patient populations to try to identify duplicate records. There are often cases that are flagged as possible duplicates, but are known not to be (twins share the same last name, date of birth, etc.). In those cases, the record administrator would like to explicitly mark the cases as not duplicates so that future runs of patient matching algorithms will not propose them as potential matches.

Adding an "is-not" code to the LinkType will allow this to take place.