H.4.2 AE Specifications
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### H.4.2 AE Specifications

#### H.4.2.1 PHARMACY-SCP Application Entity Specification

##### H.4.2.1.1 SOP Classes

The PHARMACY-SCP AE provides Standard Conformance to the following DICOM SOP Classes:

Table H.4.2-1. SOP Classes for PHARMACY-SCP AE

SOP Class Name | SOP Class UID | SCU | SCP
--- | --- | --- | ---
Verification | 1.2.840.10008.1.1 | No | Yes
Product Characteristics Query | 1.2.840.10008.5.1.4.41 | No | Yes
Substance Approval Query | 1.2.840.10008.5.1.4.42 | No | Yes

##### H.4.2.1.2 Association Policies

###### H.4.2.1.2.1 General

The PHARMACY-SCP AE will never initiate Associations; it only accepts Association Requests from external DICOM AEs. The PHARMACY-SCP AE will accept Associations for Verification (C-ECHO) and Query (C-FIND) requests.

The DICOM standard Application Context Name for DICOM is always accepted:

Table H.4.2-2. DICOM Application Context for PHARMACY-SCP AE

Application Context Name | 1.2.840.10008.3.1.1.1

###### H.4.2.1.2.2 Number of Associations

The PHARMACY-SCP AE can support multiple simultaneous Associations. Each time the PHARMACY-SCP AE receives an Association, a child process will be spawned to process the Verification or Query request. The maximum number of child processes, and thus the maximum number of simultaneous Associations that can be processed, is set by configuration. The default maximum is 10 in total.

Table H.4.2-3. Number of Simultaneous Associations as a SCP for PHARMACY-SCP AE

Maximum number of simultaneous Associations | 10 (Configurable)

###### H.4.2.1.2.3 Asynchronous Nature

The PHARMACY-SCP AE does not support asynchronous communication (multiple outstanding transactions over a single Association). All Association requests must be completed and acknowledged before a new operation can be initiated.

Table H.4.2-4. Asynchronous Nature as a SCP for PHARMACY-SCP AE

Maximum number of outstanding asynchronous transactions | 1 (Not Configurable)

###### H.4.2.1.2.4 Implementation Identifying Information

The implementation information for the Application Entity is:

Table H.4.2-5. DICOM Implementation Class and Version for PHARMACY-SCP AE

Implementation Class UID | 1.840.xxxxxxx.yyy.etc…
Implementation Version Name | EX_VERS_01

Note that all EXAMPLE-MEDICATION-SYSTEM-GATEWAY AEs use the same Implementation Class UID and Implementation Version Name. This Version Name is updated with each new release of the product software, as the different AE versions are never released independently.

##### H.4.2.1.3 Association Initiation Policy

The PHARMACY-SCP AE does not initiate Associations.

##### H.4.2.1.4 Association Acceptance Policy

###### H.4.2.1.4.1 Activity - Handling Query Requests

###### H.4.2.1.4.1.1 Description and Sequencing of Activity

The PHARMACY-SCP AE accepts Associations only if they have valid Presentation Contexts. If none of the requested Presentation Contexts are accepted then the Association Request itself is rejected. It can be configured to only accept Associations with certain hosts (using TCP/IP address) and/or Application Entity Titles.

The following sequencing applies to the PHARMACY-SCP AE for handling queries (C-FIND-Requests) :

1. Peer AE opens an Association with the PHARMACY-SCP AE.

2. Peer AE sends a C-FIND-RQ Message

3. If the query is for a Substance Administration Approval, PHARMACY-SCP AE requests basic patient demographic data (e.g., name, sex) from the Patient Registration System

4. PHARMACY-SCP AE translates the query into a request for the Pharmacy Information System (for either Product Information or for Substance Administration Approval), which responds with the requested data (or an indication of no matching data for the query).

5. If matching information is provided, PHARMACY-SCP AE returns a C-FIND-RSP Message to the peer AE with the matching information.

6. A final C-FIND-RSP is sent indicating that the matching is complete.

7. Peer AE closes the Association. Note that the peer AE does not have to close the Association immediately. Further C-FIND Requests can be sent over the Association before it is closed.

The PHARMACY-SCP AE may reject Association attempts as shown in the table below. The Result, Source and Reason/Diag columns represent the values returned in the corresponding fields of an ASSOCIATE-RJ PDU (see Section 9.3.4 “A-ASSOCIATE-RJ PDU Structure” in PS3.8 ). The following abbreviations are used in the Source column:

1. 1 - DICOM UL service-user

2. 2 - DICOM UL service-provider (ASCE related function)

3. 3 - DICOM UL service-provider (Presentation related function)

Table H.4.2-6. Association Rejection Reasons

Result | Source | Reason/Diag | Explanation
--- | --- | --- | ---
2 - rejected-transient | c | 2 - local-limit-exceeded | The (configurable) maximum number of simultaneous Associations has been reached. An Association request with the same parameters may succeed at a later time.
2 - rejected-transient | c | 1 - temporary-congestion | No Associations can be accepted at this time due to the real-time requirements of higher priority activities or because insufficient resources are available (e.g., memory, processes, threads). An Association request with the same parameters may succeed at a later time.
1 - rejected-permanent | a | 2 - application-context-name-not-supported | The Association request contained an unsupported Application Context Name. An association request with the same parameters will not succeed at a later time.
1 - rejected-permanent | a | 7 - called-AE-title-not-recognized | The Association request contained an unrecognized Called AE Title. An Association request with the same parameters will not succeed at a later time unless configuration changes are made. This rejection reason normally occurs when the Association initiator is incorrectly configured and attempts to address the Association acceptor using the wrong AE Title.
1 - rejected-permanent | a | 3 - calling-AE-title-not-recognized | The Association request contained an unrecognized Calling AE Title. An Association request with the same parameters will not succeed at a later time unless configuration changes are made. This rejection reason normally occurs when the Association acceptor has not been configured to recognize the AE Title of the Association initiator.
1 - rejected-permanent | b | 1 - no-reason-given | The Association request could not be parsed. An Association request with the same format will not succeed at a later time.

The PHARMACY-SCP AE will close the Association under the exceptional circumstances listed in Table H.4.2-7.

Table H.4.2-7. PHARMACY-SCP AE Communication Failure Behavior

Exception | Behavior
--- | ---
Timeout expiry for an expected DICOM Message Request (DIMSE level timeout). I.e. The PHARMACY-SCP AE is waiting for the next C-FIND Request on an open Association but the timer expires. | The Association is aborted by issuing a DICOM A-ABORT. Error message is output to the Service Audit Trail.
Timeout expiry for an expected DICOM PDU or TCP/IP packet (Low-level timeout). I.e. The PHARMACY-SCP AE is waiting for the next message PDU but the timer expires. | The Association is aborted by issuing a DICOM A-ABORT. Error message is output to the Service Audit Trail.
Association aborted by the SCU or the network layers indicate communication loss (i.e., low-level TCP/IP socket closure) | Error message is output to the Service Audit Trail.

###### H.4.2.1.4.1.2 Accepted Presentation Contexts

The PHARMACY-SCP AE will accept Presentation Contexts as shown in Table H.4.2-8.

Table H.4.2-8. Accepted Presentation Contexts By the PHARMACY-SCP AE

Presentation Context Table
Abstract Syntax | Transfer Syntax | Role | Extended Negotiation
--- | --- | --- | ---
Name | UID | Name | UID
Verification | 1.2.840.10008.1.1 | DICOM Implicit VR Little Endian | 1.2.840.10008.1.2 | SCP | None
Product Characteristics Query | 1.2.840.10008.5.1.4.41 | DICOM Implicit VR Little Endian | 1.2.840.10008.1.2 | SCP | None
DICOM Explicit VR Little Endian | 1.2.840.10008.1.2.1
Substance Approval Query | 1.2.840.10008.5.1.4.42 | DICOM Implicit VR Little Endian | 1.2.840.10008.1.2 | SCP | None
DICOM Explicit VR Little Endian | 1.2.840.10008.1.2.1

###### H.4.2.1.4.1.3 SOP Specific Conformance for Verification SOP Class

The PHARMACY -SCP AE provides standard conformance to the Verification SOP Class as an SCP.

###### H.4.2.1.4.1.4 SOP Specific Conformance for Product Characteristics Query SOP Class

The PHARMACY-SCP AE supports the Return Key Attributes shown in Tables H.4.2-9 and H.4.2-10. Only those attributes requested in the query identifier are returned. Note that queries about devices are not supported.

Table H.4.2-9. Return Key Attributes Supported for Product Characteristics Query

Product Package Identifier | (0044,0001) | Returned with query match value
--- | --- | ---
Product Type Code Sequence | (0044,0007) | RxNorm coded type of drug
Manufacturer | (0008,0070) |
Product Name | (0044,0008) |
Product Description | (0044,0009) |
Product Lot Identifier | (0044,000A) |
Product Expiration DateTime | (0044,000B) |
Product Parameter Sequence | (0044,0013) | See Table H.4.2-10 for parameters supported
Pertinent Documents Sequence | (0038,0100) | Zero or one item returned
>Retrieve URI | (0040,E010) |

Table H.4.2-10. Product Parameter Sequence Item Concepts Supported

Concept Name Code Sequence (0040,A043)
(G-D705, SRT, "Volume")
(G-C52F, SRT, "Active Ingredient")

Only the ASCII (DICOM Default) character set is supported by the Pharmacy Information System; Specific Character Set (0008,0005) is not used.

###### H.4.2.1.4.1.5 SOP Specific Conformance for Substance Approval Query SOP Class

The PHARMACY-SCP AE supports the Matching Key Attributes shown in Table H.4.2-11. It can be configured to match on Patient ID, or on Admission ID, or on a combination of Patient ID and Issuer of Patient ID, or on a combination of Admission ID and Issuer of Admission ID. As required by the SOP Class, one of Patient ID or Admission ID must be present in the query, as must Product Package Identifier and Administration Route Code Sequence. Note, however, that the Pharmacy Information System does not support verification of administration route. Also note that queries about devices are not supported.

Table H.4.2-11. Matching Key Attributes Supported for Substance Approval Query

Patient ID | (0010,0020)
Issuer of Patient ID | (0010,0021)
Admission ID | (0038,0010)
Issuer of Admission ID | (0038,0011)
Product Package Identifier | (0044,0001)
Administration Route Code Sequence | (0054,0302)
>Code Value | (0008,0100)
>Coding Scheme Designator | (0008,0102)

The PHARMACY-SCP AE supports the Return Key Attributes shown in Table H.4.2-12. Only those attributes requested in the query identifier are returned.

Table H.4.2-12. Return Key Attributes Supported for Substance Approval Query

Patient's Name | (0010,0010) | Obtained from Patient Registration System
--- | --- | ---
Patient ID | (0010,0020) | Obtained from Patient Registration System if AE configured for Admission ID matching, or Admission ID + Issuer of Admission ID matching
Issuer of Patient ID | (0010,0021) | Returned only if AE configured for Patient ID + Issuer of Patient ID matching
Patient's Birth Date | (0010,0030) | Obtained from Patient Registration System
Patient's Sex | (0010,0040) | Obtained from Patient Registration System
Admission ID | (0038,0010) | Returned only if AE configured for Admission ID matching, or Admission ID + Issuer of Admission ID matching
Issuer of Admission ID | (0038,0011) | Returned only if AE configured for Admission ID + Issuer of Admission ID matching
Product Package Identifier | (0044,0001) | Returned with query match value
Administration Route Code Sequence | (0054,0302) | Returned with query match value
Substance Administration Approval | (0044,0002) | Obtained from Pharmacy Information System
Approval Status Further Description | (0044,0003) | Obtained from Pharmacy Information System
Approval Status DateTime | (0044,0004) |

Specific Character Set (0008,0005) is returned with value ISO_IR 192 if the Patient Registration System provides non-ASCII Unicode characters in Patient Name.

###### H.4.2.1.4.1.6 PHARMACY-SCP AE C-FIND Response Behavior

The PHARMACY-SCP AE supports the C-FIND Response Status return values and behavior shown in Table H.4.2-13.

Table H.4.2-13. PHARMACY-SCP AE C-FIND Response Status Return Behavior

Service Status | Further Meaning | Error Code | Behavior
--- | --- | --- | ---
Success | Success | 0000 | Matching is complete. No final identifier is supplied.
Failure | Out of Resources | A700 | System reached the limit in memory usage for queuing requests to the Pharmacy Information System. Error message is output to as an alert to the Service Audit Trail.
Identifier does not match SOP Class | A900 | The C-FIND query identifier contains invalid Elements or values, or is missing mandatory Elements or values for the specified SOP Class. Error message is output to the Service Audit Trail.
Unable to process | C001 | The AE is unable to establish a session with the Pharmacy Information System. Error message is output to the Service Audit Trail.
Unable to process | C002 | The AE is unable to establish a session with the Patient Registration System. Error message is output to the Service Audit Trail.
Unable to process | C110 | The AE is unable to identify the Patient. Error message is output to the Service Audit Trail.
Unable to process | C120 | The AE is unable to identify the Product. Error message is output to the Service Audit Trail.
Cancel | Matching terminated due to Cancel Request | FE00 | The C-FIND SCU sent a Cancel Request. This has been acknowledged and the search for matches has been halted.
Pending | Matches are continuing and current match is supplied. | FF00 | Indicates that the successful match is returned and a further response (0000) is forthcoming. This status code is returned if all Optional keys in the query identifier are actually supported.
Matches are continuing but one or more Optional Keys were not supported. | FF01 | Indicates that the successful match is returned and a further response (0000) is forthcoming. This status code is returned if there are Optional keys in the query identifier that are not supported.

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