HL7 Component Table - EI - Entity Identifier
| Core Framework | Base Standard Profile | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Seq# | Description | Interpretation | Flags | Cardinality | Length | C.LEN | Vocabulary | Data Type | Implement | Cardinality | Vocabulary |
 EI |
|||||||||||
 1 |
Entity Identifier | [0..1] | ST | ||||||||
| 2 |
Namespace ID | [0..1] | noObject (CD VS) | IS | (CS) | ||||||
3 |
Universal ID | C Condition defined for this element [1..1] [0..0] |
ST | MAY | |||||||
| 4 |
Universal ID Type | C Condition defined for this element [1..1][0..0] |
universalIdType (CD VS) | ID | MAY | (CS) | |||||
The root for the expression is on the segment.
| Seq. | Referenced Elements | Introduction | Invariant | Comment | proposed Optionality |
|---|---|---|---|---|---|
| 3 | ? | Universal ID | |||
| 4 | ? | Universal ID Type |
Definition: The entity identifier defines a given entity within a specified series of identifiers.
The EI is appropriate for, but not limited to, machine or software generated identifiers. The generated identifier goes in the first component. The remaining components, 2 through 4, are known as the assigning authority; they identify the machine/system responsible for generating the identifier in component 1.
The specified series, the assigning authority, is defined by components 2 through 4. The assigning authority is of the hierarchic designator (HD) data type, but it is defined as three separate components in the EI data type, rather than as a single component as would normally be the case. This is in order to maintain backward compatibility with the EI’s use as a component in several existing data fields. Otherwise, the components 2 through 4 are as defined in Section 2.A.33, "HD - hierarchic designator". Hierarchic designators (HD) are unique across a given HL7 implementation.
Definition: The first component,
Definition: See Section 2.A.33.1, "Namespace ID (IS)" for definition. The component intentionally remains associated with the IS data type in v 2.7.
The assigning authority is a unique identifier of the system (or organization or agency or department) that creates the data. Refer to User-defined Table 0363 - Assigning Authority for suggested values.
Definition: See Section 2.A.33.2, "Universal ID (ST)" for definition.
Definition: Refer to HL7 Table 0301 - Universal ID Type for valid values. See Section 2.A.33.3, "Universal ID Type (ID)," for definition.
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