ADT_A60 - Update allergy information

Segment structure for the ADT_A60 message in HL7 v2.5.1. Cardinality is shown as [min..max]; groups are in bold.

• MSH Message header [1..1]
• SFT Software segment [0..*]
• EVN Event type [1..1]
• PID Patient identification [1..1]
• PV1 Patient visit [0..1]
• PV2 Patient visit - additional information [0..1]
• IAM Patient adverse reaction information [0..*]