HL7 ADT^A40 (Merge Patient - Patient Identifier List)
ADT^A40 is the HL7v2 merge patient - patient identifier list message, defined in HL7v2 from v2.3 through v2.8.2. Its v2.8.2 structure carries 9 segments and groups, 5 of them required.
Full message structure (v2.8.2)
Every segment and group the standard defines for ADT^A40, in order, straight from the machine-readable specification. Indented rows sit inside the repeating group above them. R is required, O optional, C conditional; ∞ means the group or segment may repeat without a defined limit.
| Segment / group | Usage | Repeats |
|---|---|---|
| MSH | R | 1 |
| SFT | O | ∞ |
| UAC | O | 1 |
| EVN | R | 1 |
| PATIENT (group) | R | ∞ |
| PID | R | 1 |
| PD1 | O | 1 |
| MRG | R | 1 |
| PV1 | O | 1 |
Which HL7v2 versions changed ADT^A40?
ADT^A40 has been defined since v2.3. Consecutive versions sharing an identical structure are grouped, so a single row spanning several versions means nothing changed across them.
| Versions | What changed |
|---|---|
| v2.3 - v2.3.1 | First defined, with 7 segments and groups. |
| v2.4 - v2.5.1 | Same segments, but usage or repeat counts changed. |
| v2.6 - v2.8.2 | Added SFT, UAC. |