Logical grouping of fields

Fields can be grouped to contain other related fields. For example, the SendingApplication HD Composite Field is HL7 data type HD. Grouped fields are delimited using the Comp Separator value.

When a field definition contains another field which defines a group of fields, the data type of the field within the definition is defined as a "Sub", or subcomponent in the schema. For example, ErrorCodeAndLocation ELD Composite contains CodeIdentifyingError CWE Sub. Both the ELD and CWE data types contain groups of related fields and can be used within a segment, or within another field. Subcomponent elements are delimited using the subcomponent separator value.

Fields can repeat and are identified as a Repeat Field, for example, ErrorLocation ELD Repeat Field. Repeating data types are delimited using the repetition sseparator value.