For "admitted" patients, the A11 event is sent when an A01 (admit/visit notification) event is canceled, either because of an erroneous entry of the A01 event, or because of a decision not to admit the patient after all.
For "non-admitted" patients, the A11 event is sent when an A04 (register patient) event is canceled, either because of an erroneous entry of the A04 event, or because of a decision not to check the patient in for the visit after all. To cancel an A05 (pre-admit a patient) event, use the A38 (cancel pre-admit), which is new for Version 2.3 of this Standard.
The fields included when this message is sent should be the fields pertinent to communicate this event. When other important fields change it is recommended that the A08 (update patient information) event be used instead.
ADT ADT Message Chapter
MSH Message Header 2
EVN Event Type 3
PID Patient Identification 3
[PD1] Additional Demographics 3
PV1 Patient Visit 3
[ PV2 ] Patient Visit - Additional Info. 3
[ { DB1 } ] Disability Information 3
[ { OBX } ] Observation/Result 7
[ { DG1 } ] Diagnosis Information 6
ACK General Acknowledgment Chapter
MSH Message Header 2
MSA Message Acknowledgment 2
[ ERR ] Error 2