HL7 V2 ADT
Message Specifications

Message Acknowledgment Tabular View

ADT_ACK
MSH [1..1] [R]
MSH.1 [Field Separator] [1..1] [R] (ST)
Definition: This field contains the separator between the segment ID and the first real field, MSH-2-encoding characters. As such it serves as the separator and defines the character to be used as a separator for the rest of the message. Recommended value is |, (ASCII 124).
MSH.2 [Encoding Characters] [1..1] [R] (ST)
Definition: This field contains the four characters in the following order: the component separator, repetition separator, escape character, and subcomponent separator. Recommended values are ^~\& (ASCII 94, 126, 92, and 38, respectively). These encoding characters is valid only for pipe-and-hat encoding. When message is translated into XML these encoding characters are carried in MSH.2 element.
MSH.3 [Sending Application] [1..1] [R] (HD) { Table : 0361-Application }
Definition: This field uniquely identifies the sending application among all other applications within the network enterprise.
MSH.4 [Sending Facility] [1..1] [R] (HD) { Table : 0362-Facility }
Definition: This field further describes the sending application, MSH-3-sending application. ITK compliant systems use 3 characters ODS code for NHS organization. 5 Character codes may also be used when there are more than one sending facilities within NHS organization or this field is used to carry data at more granular level.
MSH.5 [Receiving Application] [1..1] [R] (HD) { Table : 0361-Application }
Definition: This field uniquely identifies the receiving application among all other applications within the network enterprise. Where the message is being broadcast by PAS to a number of consumer systems via the toolkit, this field should be populated with 'ROUTE' to indicate that the toolkit will take responsibility for onward routing.
MSH.6 [Receiving Facility] [1..1] [R] (HD) { Table : 0362-Facility }
Definition: This field identifies the receiving application among multiple identical instances of the application running on behalf of different organizations. ITK compliant systems use 3 character ODS code for NHS organization, or in the case of broadcast (see note above) may populate with 'ROUTE'. 5 Character codes may also be used when there are more than one receiving facilities within NHS organization or this field is used to carry data at more granular level.
MSH.7 [Date/Time of Message] [1..1] [R] (TS)
Definition: This field contains the date/time that the sending system created the message. If the time zone is specified, it will be used throughout the message as the default time zone. To ensure consistency of message processing all participating systems should be registered on the same consistent time server.
MSH.8 [Security] [0..*] [X] (ST)
not used in ITK
MSH.9 [Message Type] [1..1] [R] (MSG)
Definition: This field contains the message type, trigger event, and the message structure ID for the message. Note, it is important to ensure that the correct format is used in this field. The toolkit uses the third element e.g. ADT_A01 to select the appropriate WSDL and Schema for message handling.
MSH.10 [Message Control ID] [1..1] [R] (ST)
Definition: This field contains a number or other identifier that uniquely identifies the message. The receiving system echoes this ID back to the sending system in the Message acknowledgment segment (MSA).
MSH.11 [Processing ID] [1..1] [R] (PT)
Definition: This field is used to decide whether to process the message as defined in HL7 Application (level 7) Processing rules. The first component defines whether the message is part of a production, training, or debugging system.
MSH.12 [Version ID] [1..1] [R] (VID)
Definition: This field is matched by the receiving system to its own version to be sure the message will be interpreted correctly.
MSH.13 [Sequence Number] [0..1] [O] (NM)
Definition: A non-null value in this field implies that the sequence number protocol is in use. This numeric field is incremented by one for each subsequent value. In a multi-hop environment, it is possible that messages may be received out of sequence. This number can be used in conjunction with the Date/Time Value to assist in the identification of messaging which happens out of sequence. Further detail on this can be found in the accompanying document 01 - ITK - Toolkit Architecture Overview.
MSH.14 [Continuation Pointer] [0..1] [O] (ST)
Definition: This field is used to define continuations in application-specific ways. Only the sender of a fragmented message values this field.
MSH.15 [Accept Acknowledgment Type] [0..*] [X] (ID)
not supported in ITK
MSH.16 [Application Acknowledgment Type] [0..*] [X] (ID)
not supported in ITK
MSH.17 [Country Code] [1..1] [R] (ID) { Table : 0399-CountryCode }
Definition: This field contains the country of origin for the message. Field Length: 3 characters. e.g. 'GBR' Use ISO 3166-1 Alpha 3 (3 character codes). Refer to latest version of HSCIC ITK HL7 V2 Reference Tables - Table 0399
MSH.18 [Character Set] [0..1] [C] (ID) { Table : 0211-AlternateCharacterSets }
Definition: This field contains the character set for the entire message. Refer to latest version of HSCIC ITK HL7 V2 Reference Tables - Table 0211.
MSH.19 [Prinicipal Language of Message] [1..1] [R] (CE) { Table : 0296-PrimaryLanguage }
Definition: This field contains the principal language of the message. Field Length: 2 characters. e.g. 'EN' Use ISO Table 639-1 Alpha 2 (2 character codes). Refer to latest version of HSCIC ITK HL7 V2 Reference Tables - Table 0296.
MSH.20 [Alternate Character Set Handling Scheme] [0..*] [X] (ID)
not used in ITK
MSH.21 [Message Profile Identifier] [1..*] [R] (ID)
Definition: Sites use this field to assert adherence to a Conformance Statement published by ITK. This is a mandatory specification conformance statement, indicates which version of the ITK the message is compliant with e.g. ITKv1.0.
MSA [1..1] [R]
MSA.1 [Acknowledgment Code] [1..1] [R] (ID) { Table : 0008-AcknowledgmentCode }
Definition: This field contains an acknowledgment code Refer to latest version of HSCIC ITK HL7 V2 Reference Tables - Table 0008.
MSA.2 [Message Control ID] [1..1] [R] (ST)
Definition: This field contains the message control ID of the message sent by the sending system. It allows the sending system to associate this response with the message for which it is intended.
MSA.3 [Text Message] [0..1] [O] (ST)
Definition: This optional field further describes an error condition. This text may be printed in error logs or presented to an end user.
MSA.4 [Expected Sequence Number] [0..1] [O] (NM)
Definition: This optional numeric field is used in the sequence number protocol.
MSA.5 [Delayed Acknowledgment Type] [0..*] [B] (ID)
not used in ITK
MSA.6 [Error Condition] [0..1] [O] (CE) { Table : 0357-MessageErrorConditionCodes }
Definition: This field allows the acknowledging system to use a user-defined error code to further specify AR or AE type acknowledgments. This field is a generalized replacement for MSA-3-text message. Refer to latest version of HSCIC ITK HL7 V2 Reference Tables - Table 0357.
ERR [0..1] [O]
ERR.1 [Error Code and Location] [1..*] [R] (ELD)
Definition: This field identifies an erroneous segment in another message. The second component is an index if there is more than one segment of type <segment ID>. For systems that do not use the HL7 Encoding Rules, the data item number may be used for the third component. The fourth component is Message error condition code.