LOINC description : Area for retaining behavior portion (1 digit) of the ICD-O-1 or field trial morphology
codes entered before a conversion to ICD-O-2. See grouped data item Morph (73-91)
ICD-O-1 [1970] in Appendix E. The item name includes years 73-91. However, some states
may have used the codes for cases before 1973. It is a subfield of the morphology
code.... NAACCR Data Standards and Data Dictionary Version 11;