Whether the field is required, optional, or conditional in a segment. The designations are:
R |
- |
required |
O |
- |
optional |
C |
- |
conditional on the trigger event or on some other field(s) |
X |
- |
not used with this trigger event |
B |
- |
left in for backward compatibility with previous versions of HL7 |
Note: For Versions 2.3 and higher: the optionality of fields should be explicitly documented in the segment field definitions that follow each segment definition table; if the optionality of fields within a segment changes depending on the trigger event, that optionality should also be explicitly documented. |
Note: For fields defined by HL7 data types containing multiple components or subcomponents, the optionality of a given component or sub-component must be specified in the detailed field definitions that follow the formal segment attribute tables. (See also Sections 2.7, "MESSAGE DELIMITERS," 2.8, "Data types," and 2.10, "Message construction rules"). |
In the segment attribute tables this information is in a column labeled OPT.