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Virtual Medical Record for Clinical Decision Support panel HL7.VMR-CDS https://s.details.loinc.org/LOINC/74028-2.html?sections=ComprehensiveThis appendix make use of aspects from

A9.1 Introduction

The HL7v2 Virtual Medical Record (VMR) is a way to implement a structured information atomically in a series of HL7 OBX segments following a template methodology. 

It is based upon the HL7 Publication "HL7 Version 2 Implementation Guide: Implementing the Virtual Medical Record for Clinical Decision Support (vMR-CDS), Release 1 " (you may need an account with HL7 International to download). Refer to that document for a deeper understanding and discussion of the methodology. This appendix will simply provide a prescription for its implementation in a simple way.

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Suggested

OBX-5 Observation value

or

Value Set or Constraint

...

OBX-14 Date/time of the observation is valued

(Y=Yes, N=No)

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Value Set (

15240007^Current^SCT

410511007^Current or past^SCT

410587003^Past - specified^SCT

410588008^Past - unspecified^SCT

410589000^All times past^SCT

6493001^Recent^SCT

)

If the temporal context is unspecified, then 410511007^Current or past^SCT is the assumed value.

...

The HL7v2 Virtual Medical Record is also defined by the LOINC as "Virtual Medical Record for Clinical Decision Support panel HL7.VMR-CDS" (74028-2). The panel definition can be viewed at the following URL: https://s.details.loinc.org/LOINC/74028-2.html?sections=Comprehensive

A9.2 Implementing the HL7v2 Virtual Medical Record with OBX segments

A9.2.1 Specifying the HL7v2 VMR is in use.

When using the HL7v2 VMR a header OBX must be present which indicates that a report template is in use. In the header, OBX-3 field must have the value "74028-2^Report template ID^LN", and the template that is in use OBX-5 must, and also specify an OBX-4 sub-ID which must be a dotted decimal value (for simplicity "1" has been specified as the root sub ID). This header OBX must have a OBX-2 Datatype field value of "RP" (See 3.20 RP - Reference Pointer). OBX-5 must be valued as "HL7V2-VMR.v1^HL7V2 VMR&99A-9AAC5A649D18B6F2&L^TX^Octet-stream".

Subsequently all other OBX segments present that form part of the HL7.VMR must have dotted sub id based on this OBX-4 sub-ID this header OBX.

Therefore as an example, the first OBX is static and must be as follows:

OBX|1|RP|74028-2^Report template ID^LN|1|HL7V2-VMR.v1^HL7V2 VMR&99A-9AAC5A649D18B6F2&L^TX^Octet-stream||||||F

A9.2.2 Implementing each element of the HL7v2 VMR

The HL7v2 VMR OBX implementation table below defines the elements of the VMR and provides values that must be used in various OBX fields as indicated by the column headings. 

Each VMR element must be implemented as an OBX, the values of which will be discussed following the table.

When the row in the table has a VMR Datatype column of ENTRY, SECTION, STRUCTURAL, COLLECTION then the prescribed values in the table must be used. 

Technically, OBX for VMR Data SECTIOHTTPAccessControlAllowOriginManagerN, STRUCTURAL and COLLECTION are optional as the structure is implied by the dotted decimal structured OBX-4 Observation sub-ID. However, including these OBX segments can be useful to viewers of the atomic data but non-essential for computed interpretation of the actual content.

A9.2.2.1 HL7v2 VMR OBX implementation table

Refer to the legend table that follows after this table which explains the colours used. The colours are redundant and are indicative of certain values in the VMR Datatype column.

Anchor
A9.T.1 A9.T.1

A9.T.1 HL7v2 VMR OBX implementation table

Legend:

Rows marked VMR STRUCTURAL should not be written to OBX segments and are present in the table are purely virtual and are to assist with understanding the hierarchy. They should be allocated a dotted subID however, on which all child elements should be prefixed with this subID. 

By example consider the history of past illness from the above table. Here is the subset for convenience.

For each repetition of a structural group 

For example, the first instance of a past illness the OBX-4 sub-ID should be 1.2.1.1, for the second 1.2.1.2.

Based on this the Past Illness OBXes for the first illness should have a OBX-4 sub-ID value of 1.2.1.1.1, and for the second illness, the OBX-4 sub-ID value should be 1.2.1.2.1.

OBX|6|CE|70949-3^^LN|1.2|11348-0^History of Past Illness^LN^417662000^History of Past Illness^SCT||||||F
OBX|7|CE|11349-8^Past Illness^LN|1.2.1.1.1|50711007^Viral hepatitis C^SCT||||||F
OBX|8|CE|408731000^Temporal Context^SCT|1.2.1.1.2|410584005^Current - specified^SCT||||||F
OBX|9|DR|11368-8^Illness Dates^LN|1.2.1.1.3|20090107||||||F
OBX|10|CE|11349-8^Past Illness^LN|1.2.1.2.1|6142004^Influenza^SCT||||||F
OBX|11|CE|408731000^Temporal Context^SCT|1.2.1.2.2|410587003^Past - specified^SCT||||||F
OBX|12|DR|11368-8^Illness Dates^LN|1.2.1.2.3|20170131^20170318||||||F

OBX 7,8,9 are part of the first illness as their OBX-4 subID is prefixed with 1.2.1.1.

OBX 10,11,12 are part of the second illness as their OBX-4 subID is prefixed with 1.2.1.2.

The Report Template OBX must be specified and its OBX-4 column SubID must be a dotted decimal value, for this profile "1" has been specified as the root sub ID. All other HL7.VMR OBX subID should have dotted sub id based on this.

The first OBX is static and should be as follows:

OBX|1|RP|74028-2^Report template ID^LN|1|HL7V2-VMR.v1^HL7V2 VMR&99A-9AAC5A649D18B6F2&L^TX^Octet-stream||||||F

OBX|2|CWE|73983-9^^LN^CLUSTER^^EN 13606|1.1|^History of Presenting Complaint||||||F

OBX-2, OBX-3 values must be as listed in the table.

OBX-5 value domains are suggested and recommended. However, systems should use the values that they have available in their systems.

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Legend:

A9.2.2.2 OBX-2 DataType (ID)

Each OBX must have it's OBX-2 value as specified exactly as per the HL7v2 VMR OBX implementation table.

A9.2.2.3 OBX-3 Observation Identifier (CE)

A9.2.3.4 OBX-4 Observation sub-ID (ST)

In the table A9.T.1 OBX-4 subIDs are dotted decimals that start with "1" which is the root OBX-4 subID for all elements of the HL7v2 Virtual Medical Record. The root value "1" has been specified in the above table to aid in simplicity. Theoretically other subID root values could be used instead of "1", but this value must be practical in most cases.

Observations which are not specified by the HL7v2 VMR must not have a OBX-4 subID sharing the same root.

Rows marked VMR DATATYPE column as STRUCTURAL (red rows) must not be written to OBX segments and are present in the table are purely virtual and are to assist with understanding the hierarchy. They must be allocated a dotted subID however, on which all child elements must be prefixed with this subID. 

A9.2.3.4.1 Example of use of Past Illness VMR elements

OBX|6|CE|70949-3^^LN|1.2|11348-0^History of Past Illness^LN^417662000^History of Past Illness^SCT||||||F
OBX|7|CE|11349-8^Past Illness^LN|1.2.1.1.1|50711007^Viral hepatitis C^SCT||||||F
OBX|8|CE|408731000^Temporal Context^SCT|1.2.1.1.2|410584005^Current - specified^SCT||||||F
OBX|9|DR|11368-8^Illness Dates^LN|1.2.1.1.3|20090107||||||F
OBX|10|CE|11349-8^Past Illness^LN|1.2.1.2.1|6142004^Influenza^SCT||||||F
OBX|11|CE|408731000^Temporal Context^SCT|1.2.1.2.2|410587003^Past - specified^SCT||||||F
OBX|12|DR|11368-8^Illness Dates^LN|1.2.1.2.3|20170131^20170318||||||F

A9.2.3.5 OBX-5 Observation value (*)

OBX-5 value domains in table A9.T.1 are suggested and values only, sending systems must use the values that they have available in their systems. If common standard terminologies are available, then those can be supplied as alternative code components of the CE/CWE/CNE if a standard terminology isn't used aren't the primary coding system. Where no codes is available then only the text component must be populated.

A9.3 Value Domain Tables