Before Version 12 (through 2009 diagnosis), date fields included codes that provided information other than dates. As part of an initiative to standardize date fields, new fields were introduced to accommodate non-date information that had previously been transmitted in date fields.

10	No information whatsoever can be inferred from this exceptional value (e.g., unknown if any surgical procedure site was performed).
11	No proper value is applicable in this context (e.g., no surgical procedure was performed; autopsy only case).
12	A proper value is applicable but not known. This event occurred, but the date is unknown (e.g., surgery was performed but the date is unknown).
Blank	A valid date value is provided in item RX Date Surgery [1200], or the date was not expected to have been transmitted.

Comment: This is part of the initiative of the transformation from the old NAACCR date standards to interoperable dates.