LOINC description : Provides a unique identifier for the patient consisting of the year in which the patient
was first seen at the reporting facility and the consecutive order in which the patient
was abstracted. The first four numbers specify the year and the last five numbers
are the numeric order in which the patient was entered into the registry database.
Within a registry, all primaries for an individual must have the same accession number.
The first four digits must be greater than or equal to 1944. This data item protects
the identity of the patient and allows cases to be identified on a local, state, and
national level. If the central registry preserves this number, they can refer to it
when communicating with the hospital. It also provides a way to link computerized
follow-up reports from hospitals into the central database... NAACCR Data Standards
and Data Dictionary Version 11;