Update on NHS Digital’s request for addition of SEID to SNOMED CT terminology system

Post #359 Shortlink: https://wp.me/pKrrB-58W

Update on NHS Digital’s request for addition of Systemic exertion intolerance disease (SEID) to SNOMED CT terminology system

In February 2015, a panel convened by the Institute of Medicine (IOM), now the National Academy of Medicine (NAM), published a report on ME, CFS called “Beyond Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Redefining an Illness.”[1]

The panel undertook an evidence review and formulated recommendations which had included proposals for new diagnostic criteria and the suggestion of the name “Systemic exertion intolerance disease (SEID)”, as part of a number of recommendations put forward for review and consideration by the Report’s sponsor agencies.

Five years on:

  • The CDC has not adopted the term “Systemic exertion intolerance disease (SEID)”. In preference, the CDC uses “ME/CFS” on its website clinical information pages and for its Continuing Medical Education (CME) activities.
  • The NCHS-CDC have not added the SEID term to ICD-10-CM, an adaptation of the WHO’s ICD-10, that is mandatory in the US for assigning diagnostic codes for medical billing and reimbursement.
  • The SEID term has not been added to the final update of the WHO’s international edition of ICD-10 (Version: 2019).
  • The SEID term has not been added to the SNOMED CT US Edition by its managers, the National Library of Medicine (NML), either as a new Concept code, or as a Synonym or Child term.
  • The IOM panel’s Report formed part of the literature review for the revision of the ICD-10 G93.3 legacy categories. The WHO and the ICD-11 CSAC and MSAC committees have not included the SEID term in ICD-11.
  • The IOM panel’s suggested case definition has not been subject to field testing by, or on behalf of the CDC. Several studies published since the Report’s release concluded that the proposed SEID case definition lacks reliability and specificity; discussed the unintended consequences of not specifying exclusionary illnesses; and noted the lack of acceptability to patients of the proposed case definition and proposed SEID nomenclature.

A couple of minutes on Google demonstrates that some websites providing clinical information to physicians, healthcare professionals and patients are referring to “Systemic exertion intolerance disease” as though the term had been tested, evaluated and adopted by US federal agencies — when this is not the case.

In the March 2020 issue of the ME Global Chronicle, I reported on a request submitted by NHS Digital in November 2019 for addition of the “Systemic exertion intolerance disease (SEID)” term to the SNOMED CT terminology system.

SNOMED CT is used in over 30 countries and is the recommended terminology system in the UK, US, Canada, New Zealand and Australia [2].

For NHS England, SNOMED CT UK Edition is the mandatory terminology system across all primary and secondary healthcare settings. The system is used by clinicians in electronic medical records (EMRs), at the point of care, to record findings, symptoms, diagnoses, interventions, procedures etc.

The UK Edition of SNOMED CT terminology system is managed by NHS Digital [3].

Authorized users can register to submit requests for changes or additions to the terminology system via an NHS Digital submission portal. Requests that meet criteria for potential addition to the SNOMED CT International Edition are referred on for consideration by SNOMED International’s terminology specialists.

Submission #30104 (November 30, 2019) requested addition of the term “Systemic exertion  intolerance disease” as a Synonym under the existing SNOMED CT Concept: 52702003 Chronic fatigue syndrome [4].

The request appeared to originate from within the NHS (or other authorized SNOMED CT user) as no other class of stakeholder is referenced as the original requester.

The rationale text in support of request #30104 can be read on the NHS Digital Request Submission Portal, here: http://bit.ly/39Pz4vy

After drawing attention to this request on Twitter, I was contacted in March by a senior member of SNOMED International’s team.

I was advised that request #30104 had been submitted for consideration for addition to the SNOMED CT International Edition; that the request had already been processed and pending any further changes, would be implemented in the International Edition’s July release.

(Note: If the term “Systemic exertion intolerance disease (SEID)” was approved for addition to the July 2020 International Edition, the term would then be absorbed into the various national editions when they released their next updates.)

As the IOM panel’s proposed case definition and suggested term have not undergone field testing and evaluation; as the SEID term has not been adopted by US federal agencies; and as NCHS-CDC has made no decision to assign a code for SEID in the US ICD-10-CM for medical billing and reimbursement, it would be premature to approve a request for addition to the SNOMED CT International Edition.

These concerns for the potential addition of an untested, unadopted term to the SNOMED CT system were passed back to SNOMED International’s terminology specialists for their consideration.

In early June, I was informed that the terminology team had reviewed the information provided and concluded that adding “Systemic exertion intolerance disease” as a synonym is premature; that approval of this request had been retracted and SEID would not be included in the July release.

This was further confirmed on a SNOMED CT internal production page (see last entry under heading: “Concepts to be removed completely from the Alpha release content”): https://bit.ly/2Xed60V

The July 2020 release of the International Edition was published on July 31: https://bit.ly/39HA1a2

I can confirm that the two Synonyms terms that had been added under 52702003 Chronic fatigue syndrome for the Alpha production release:

● 3902795018 – SEID – systemic exertion intolerance disease
● 3902796017 – Systemic exertion intolerance disease

have been removed for the finalised July 2020 release*.

*In the event of a request for a change or addition to SNOMED CT not being accepted there is a formal appeals process and the submitter may request a further review of the decision. SNOMED International has confirmed that NHS Digital has not appealed against the decision not to add SEID to the finalised July 2020 release.

An abridged version of this post can be downloaded in PDF format here: https://bit.ly/2XeeS2e


1 Committee on the Diagnostic Criteria for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome; Board on the Health of Select Populations; Institute of Medicine. Beyond Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Redefining an Illness. Washington (DC): National Academies Press (US); Feb 2015. https://www.ncbi.nlm.nih.gov/pubmed/25695122

2 SNOMED CT International Edition browser and browsers for 14 national editions: https://browser.ihtsdotools.org/

3 NHS Digital SNOMED CT browser: http://bit.ly/38OqL1R

4 NHS Digital SNOMED CT Submission Portal: Request 30104:


Clinical classifications like ICD-10 and the SNOMED CT terminology system are complementary and serve different purposes. ICD-10 is used after the event by clinicians and coders and focuses on diagnostic coding and data recording for statistical and epidemiological analysis, reimbursement and  resource allocation.

SNOMED CT is used by clinicians in electronic medical records (EMRs), at the point of care, to record findings, symptoms, diagnoses, interventions, procedures etc.

Each clinical concept or phrase is assigned a unique SCTID code to provide a standardised, machine readable terminology for recording and sharing clinical information across multiple health care settings. SCTID codes are mapped to ICD-10 and to ICPC-2e codes for interoperability.

SNOMED CT is considered to be the most comprehensive, multilingual healthcare terminology in the world. It is used in over 30 countries and is the recommended terminology system in the UK, US, Canada, New Zealand and Australia.

SNOMED CT International Edition releases two updates a year. A number of countries maintain national editions which automatically incorporate the updated content from the core SNOMED CT International releases but may also include country specific terminology. The national editions release twice yearly updates on a staggered schedule and their current content may not reflect the changes and additions to the most recent release of the International Edition.

SNOMED CT does not regulate which concepts should or should not be used in clinical records, but makes concepts available in response to requests from stakeholders and in accordance with its editorial and content development principles [1].

Since April 2018, SNOMED CT UK Edition [2] has been the mandatory terminology system for use in NHS primary care, replacing the Read Code (CTV3) terminology system which is now retired. SNOMED CT UK Edition was scheduled for adoption across all clinical, secondary care and mental health settings from April 2020.

Browsers for the SNOMED CT International Edition and the national editions for Australia, Belgium, Canada, Denmark, Netherlands, Sweden, US and a number of other countries can be accessed here:

SNOMED International SNOMED CT Browser: http://browser.ihtsdotools.org/

1 SNOMED CT International Release Content Development:

2 The SNOMED CT UK Edition is managed by NHS Digital, as the designated UK National Release Centre. A public browser can be accessed here: https://termbrowser.nhs.uk/


World Health Organization finally releases next edition of the International Classification of Diseases (ICD-11)

Post #339 Shortlink: https://wp.me/pKrrB-4nC

(Key links from this post are also available on the ICD-11 2018 tab page.)

After 11 years in development and four extensions to the timeline, the World Health Organization (WHO) finally released a version of ICD-11 on June 18th.

Advanced preview

The WHO is presenting this June release as an “advance preview” to enable countries to start planning for implementation, prepare national translations and begin training health professionals.

ICD-11 MMS is scheduled for presentation at the World Health Assembly (WHA) in May 2019 for adoption by member states, but WHA endorsement won’t come into effect until January 1, 2022. After that date, member states can begin using the new edition for data reporting — if they are ready.

The WHO has bought itself a further three and half years in which to complete the preparation of implementation and support materials and finalize companion publications and other derivatives.

Dr Christopher Chute, chair of ICD-11’s Medical and Scientific Advisory Committee (MSAC), predicts that early implementers may require around five years to prepare their countries’ health systems for transition. Member states using a “clinical modification” of ICD are likely to take longer to develop, test and roll out a country specific adaptation.

There is no mandatory implementation date — member states will migrate to ICD-11 at their own pace and according to their countries’ specific timelines, requirements and resources.

Global adoption will likely be a patchy and prolonged process and for a period of time, WHO will be accepting data recorded using both ICD-10 and the new ICD-11 code sets.

No countries have announced implementation schedules. NHS Digital says:

NHS Digital – ICD-11 Launch

“…No decision has been made for the implementation of ICD-11 in England, however NHS Digital plan to undertake further testing of the latest release and supporting products that will inform a future decision.”

In the meantime, the mandatory classification and terminology systems for use in the NHS are ICD-10* and SNOMED CT UK Edition**.

*NHS currently mandating ICD-10 Version: 2015.
**Read Codes (CTV-2 and CTV-3) are retired. SNOMED CT became the mandatory terminology system for use in NHS primary care in April 2018. Secondary Care, Acute Care, Mental Health, Community systems, Dentistry and other systems used in the direct management of care of an individual are scheduled to adopt SNOMED CT as the mandatory clinical terminology before 1 April 2020.

Key links

ICD-11 launch News Release

Launch information and short videos: ICD-11: Classifying disease to map the way we live and die

A dedicated website for ICD-11 information has been launched: https://icd.who.int

ICD-11 Beta Draft becomes ICD-11 Maintenance Platform

The orange ICD-11 Beta drafting platform is renamed to the “ICD-11 Maintenance Platform” and will remain in the public domain as a “work in progress” between stable releases.

The content on the orange platform will change as the substantial backlog of earlier proposals and new proposals submitted since the June 2018 release are processed.

An approved proposal for an addition or other change won’t immediately be reflected in the released version of the ICD-11 MMS but carried forward for eventual incorporation into a later release, according to the update cycle for that particular class of change.

There is a current backlog of over 1000 proposals waiting to be processed. New comments and proposals will continue to be accepted (see Annex 3.7 of the Reference Guide for maintenance and update schedules and guidance on submitting new proposals).

(If you were registered with the Beta drafting platform for access to the Comments function and Proposals Mechanism your account will work for the Maintenance Platform and you will be able to access historical comments and proposals.)

The maintenance and update of ICD-11 will be advised by the Classifications and Statistics Advisory Committee (CSAC); the Medical and Scientific Advisory Committee (MSAC); the Mortality Reference Group; the Morbidity Reference Group; and the Functioning and Disability Reference Group.

It is currently unclear in which year the first update cycle is anticipated to start, i.e., whether the next stable version would be released in January 2020, or in a later year.

The ICD Revision Topic Advisory Groups and sub working groups ceased operations in October 2016 and the Joint Task Force is expected to be stood down later this year.

The ICD-11 Maintenance Platform displays both the Foundation Component and the combined Mortality and Morbidity Statistics linearization:


The ICD-11 for Mortality and Morbidity Statistics (ICD-11 MMS) 2018 version is on a new blue platform:


This platform currently displays only the MMS Linearization codes, not the Foundation Component which contains all the ICD entities. As released in June 2018, the content is planned to remain stable until January 2019, in preparation for presentation at the May 2019 World Health Assembly.

There is a coding tool here:

ICD-11 Coding Tool Mortality and Morbidity Statistics (MMS) 2018:


The ICD-11 Reference Guide (the equivalent of ICD-10’s Volume 2) is here:


(At the time of publication, there is no PDF version of the Reference Guide only an html version.)

What hasn’t been released yet?

Not all disorder “Descriptions” texts and other “Content Model” parameters have been populated and the full ICD-11 implementation package isn’t completed.

An updated ICD Revision information page states: “A suite of tools and functionality facilitate implementation and use of ICD-11.” But not all the tools and other materials listed under the Implementation Support tab are currently available.

The list also mentions “Specialty versions” but none of these are available; for example, the ICD-11 Clinical descriptions and diagnostic guidelines for Mental and Behavioural Disorders (the equivalent to ICD-10’s “Blue Book”) hasn’t been released yet.

This companion publication provides expanded clinical descriptions, differential diagnoses, diagnostic guidelines and codes for the categories in Chapter 06: Mental, behavioural and neurodevelopmental disorders including: “Essential (Required) Features, Boundaries with Other Disorders and Normality, and Additional Features sections. Additional sections (e.g., Culture-Related Features).”

Practitioners who have signed up to the Global Clinical Practice Network have had the opportunity to review and comment on drafts of the full clinical description and diagnostic guideline texts but drafts have not been available for public stakeholder review.

It’s not known whether this specialty mental disorder publication is planned to be released later this year or if the content cannot be finalized until after the ICD-11 MMS code sets have been ratified, in May 2019.

ICD-11 PHC: the revision of the 1996 publication: Diagnostic and Management Guidelines for Mental Disorders in Primary Care: ICD-10 Chapter V Primary Care Version (aka “ICD-10 PHC”) has not been released, either.

Drafts of the full texts for the disorder descriptions, as currently proposed for the 27 mental disorders for inclusion in ICD-11 PHC, are not available for public stakeholder scrutiny. There is no publicly available timeline for the finalization and release of ICD-11 PHC nor is it clear whether any additional field trials are in progress or have been recommended. NB: This publication will not be mandatory for use by WHO member states and it does not override the ICD-10 and ICD-11 code sets.

Additional materials

Brief Report from the Director-General: World Health Organization, EXECUTIVE BOARD EB143/13, 143rd session April 9, 2018, Provisional agenda item 5.2: International Statistical Classification of Diseases and Related Health Problems: update on the eleventh revision: http://apps.who.int/gb/ebwha/pdf_files/EB143/B143_13-en.pdf

Presentation Slides: ICD 11th revision, Member State Information Session Geneva, May 14, 2018, Dr John Grove, Director, Department of Information, Evidence, and Research, WHO and Dr Robert Jakob, Team Lead, Classifications, Terminologies and Standards, WHO https://dxrevisionwatch.files.wordpress.com/2018/05/icd11.pdf

Audio file from WHO Press Conference: June 14, 2018, Release of ICD-11 – the 11th revision of the International Classification of Disease, Dr Shekhar Saxena, Director, Department for Mental Health and Substance Abuse, WHO, Dr Robert Jakob, Team Lead, Classifications, Terminologies and Standards, WHO

Mp3 audio file [39:25 min]:


Presentation by Dr Michael First: Differences Between ICD-11 Classification of Mental & Behavioural Disorders and DSM-5. Nasjonal kompetansetjeneste ROP, Published July 20, 2018 [32:38 mins]


A proposal for the ICD-10 G93.3 legacy terms for ICD-11: Part One

Post #329 Shortlink: http://wp.me/pKrrB-4dV

Our Proposal and Rationale is set out in Part Two:

A proposal for the ICD-10 G93.3 legacy terms for ICD-11: Part Two

A version of ICD-11 in 2018

It’s been a long time coming and it ain’t finished yet…

The World Health Organization (WHO) has been revising ICD-10 since 2007.

After several shifts in the timeline, WHO plans to present a version of the next edition (ICD-11 MMS) at the World Health Assembly (WHA), in May 2018.

WHO won’t be seeking endorsement of the ICD-11 product in May 2018 because it won’t be ready to implement. Endorsement will be sought at some point in the future. In the meantime, a version of ICD-11 is scheduled for release later in 2018, after the May assembly. The release date has yet to be announced.


“…The World Health Organization (WHO) is currently developing the 11th revision of ICD. Once endorsed by the World Health Assembly (WHA), WHO Nomenclature regulations stipulate that Member States must use the most current revision for mortality and morbidity purposes. For this reason and to allow member countries to adopt the new revision when they are ready, WHO will brief the WHA on ICD-11 in May 2018 but will not seek endorsement at this time.”

Member states will transition from ICD-10 to the new edition at their own pace. It’s going to be several years before countries have evaluated the ICD-11 product for utility and prepared their health systems to make the transition.

At some point, data using codes from the new edition will be accepted alongside data compiled using ICD-10. WHO will continue to support ICD-10 until the majority of member states have adopted and implemented the new edition.

It will take even longer for countries like the U.S. and Canada, who use a country specific adaptation of ICD, to implement as they will need to modify the new edition to suit their countries’ health systems. The earliest Canada can implement is currently projected as 2023 [1]. The U.S.’s CDC estimate it will take at least 6 years after the codes have been ratified to prepare, field test and implement an ICD-11-CM/PCS.


Proposal deadlines

Some important deadlines for proposals for the ICD-11 Beta draft:

The deadline in order for proposals to be considered for a frozen version in March/April 2017 was 30 December 2016.

In order for proposals to be considered for inclusion in the version of ICD-11 that is scheduled for release in 2018, they needed to be submitted by March 30, 2017. So those two deadlines have been reached.

Comments by member states and improvements arising as a part of the Quality Assurance mechanism will be included with deadlines later in 2017.

According to Slide #12 in this November 2016 WHO presentation, the deadline for member state comments is May 31, 2017; the deadline for Field Testing and Quality Assurance is June 30, 2017 [2]. But these dates are unconfirmed and may have been revised since November, last year.

Proposals received after the end of May will be considered in the context of ICD-11 maintenance after 2018, when the new version will be subject to an annual update and maintenance schedule [3]. The first annual update is anticipated in 2019.

The Joint Task Force is considering naming each year’s iteration in the format: ICD 2018; ICD 2019; ICD 2020 and so on. There may never be a need for an ICD-12, since an electronic system is better able to evolve “gracefully” – as Dr Christopher Chute (Joint Task Force; Chair, Revision Steering Group) puts it – in response to advances in scientific knowledge and classificatory changes.


Deadlines for submitting comments

I have asked Dr Jakob and the Joint Task Force to clarify by what date comments on proposals that met the March 30 deadline will need to be submitted by in order to be considered in the context of the earliest release of ICD-11, in 2018.

No clarification has been forthcoming; so if you are a stakeholder considering submitting a comment on existing proposals in the Beta draft or on outstanding proposals queued in the “Proposals Mechanism” which are still going through the review process, then I would advise that you put this in hand over the next couple of weeks. If any deadline is announced, I will update at the top of this report.


Frozen release

On April 4, ICD Revision is scheduled to release a frozen version of ICD-11 MMS for field testing*. If there are any changes in this April 2017 Frozen Release that are relevant to stakeholders in the G93.3 terms, I will post an update at the top of this report.

*ICD-11 Field Trials, Information and Terms of Engagement, March 17, 2017 https://hscic.kahootz.com/gf2.ti/af/762498/122441/PDF/-/ICD11_FT_Information_and_ToE.pdf


Current status of the ICD-10 G93.3 legacy categories

The ICD-10 G93.3 legacy categories: Postviral fatigue syndrome; Benign myalgic encephalomyelitis and Chronic fatigue syndrome were taken out of the public version of the Beta draft in early 2013, with no explanation for their absence.

ICD Revision has maintained a cephalopodic grip on its intentions for these terms.

Advocates and patient organization stakeholders have been attempting to obtain transparency from ICD Revision around the Topic Advisory Group for Neurology’s proposals for these terms for over four years. During this period, stakeholders have been disenfranchised from participation in the revision process.


Questions raised in the English Parliament

15 international stakeholder organizations wrote to the ICD-11 MMS Joint Task Force, in February, in support of my call that the Joint Task Force place the matter of the continued absence of proposals for these terms on the Agenda of their February 20–22 meeting, in Cologne.

There were asked to expedite the release of proposals for public scrutiny and comment before the March 30 deadline.

This initiative was met with a disturbing level of obfuscation on the part of WHO and the Joint Task Force, especially given that ICD Revision has been promoted as an open, transparent process, inclusive of stakeholder participation.

The Countess of Mar, a long standing advocate for patients with ME and CFS, tabled two Written Questions in the House of Lords. The first is here (February 27), which received a response that raised more questions than it answered and a follow up question, here (March 16), which received an equally opaque reply.

But on March 26, the three terms were finally restored to the Beta draft – but with this caveat:

“While the optimal place in the classification is still being identified, the entity has been put back to its original place in ICD.”

Team WHO 2017-Mar-26 – 12:46 UTC

This suggests that we should view the restoration of the terms as a “placeholder” and that the work group may release revised proposals later this year.


What do we know?

WHO has confirmed that there is no intention to classify the ICD-10 G93.3 legacy terms under the Mental or behavioural disorders chapter or under the Symptoms, signs chapter.

“Team WHO” has also approved some long standing proposals for exclusions for two of these terms under Fatigue (but not yet approved an exclusion for Postviral fatigue syndrome and I have asked “Team WHO” for the rationale for this apparent anomaly, since one would anticipate that if the inclusion terms are excluded under Fatigue, the ICD concept title entity would also be excluded). Possibly, TAG Neurology has other plans for the classification of PVFS in ICD-11.

So, nearly 10 years into the revision process, it’s still unclear what the work group might be considering for these terms, when they will reach consensus, or whether alternative proposals might be released on April 4, when a frozen version of ICD-11 is scheduled for release for field testing.


How do the terms currently stand in ICD-10?

This is how the G93.3 legacy terms were represented in ICD-10:

For ICD-10, Postviral fatigue syndrome (PVFS) is the lead (or concept title) term. Benign myalgic encephalomyelitis is the inclusion term under PVFS and takes the G93.3 code. Chronic fatigue syndrome is listed only in the Index, and coded to G93.3.


How do the terms stand in ICD-11 Beta draft, now they have been restored?

Since March 26, 2017, for ICD-11 Beta draft, all three terms are currently back under the Neurology chapter, under parent: Other disorders of the nervous system. PVFS is the lead (or concept title) term. BME and CFS are both specified as inclusion terms to PVFS, in the ICD-11 equivalent of the Tabular List. The terms listed under synonyms and all other “Content Model” descriptive content appear much as the Beta had stood in 2009.

But given the caveat, it is still unknown what the work group might be considering for these terms or whether or when they might release further proposals.

Note that the recommendations of the various external work groups are advisory only. WHO classification experts and the Joint Task Joint can, and sometimes do, overrule work group decisions.

If the Topic Advisory Group for Neurology, that has responsibility for these terms, were to reach consensus and release an alternative set of proposals before 2018, these will not necessarily obtain the approval of WHO/Joint Task Joint.


Suzy Chapman and Mary Dimmock have submitted a proposal

To address this situation, U.S. advocate, Mary Dimmock, and I have collaborated on the preparation of a formal and fully referenced proposal which we submitted on March 27. Our proposal (in the PDF below) recommends that these terms should be retained in the neurological chapter, using separate codes for ME and CFS, and also makes other recommendations.

PDF: Suzy Chapman, Mary Dimmock Proposal for ICD-11


Our Proposal and Rationale is set out in Part Two:

A proposal for the ICD-10 G93.3 legacy terms for ICD-11: Part Two

For a good overview of ICD-11’s structure and functionality by NHS Digital click here


1 International Statistical Classification of Diseases and Related Health Problems, 11th Revision, Canada, Canadian Institute for Health Information (CIHI). https://www.cihi.ca/en/submit-data-and-view-standards/codes-and-classifications/icd-11

2 Presentation, Dr Robert Jakob, WHO/ICD Revision, November 2016. https://t.co/VvtZXVHZoF

3 ICD Revision Quarterly Newsletter, ICD-11 Update: January 2017. http://www.who.int/entity/classifications/ICD11January2017Newsletter.pdf


Changes to SNOMED CT and Read Codes (CTV3) for CFS, ME and PVFS

Post #327 Shortlink: http://wp.me/pKrrB-4aD

Recent changes to SNOMED CT for CFS, ME and PVFS

  • Correspondence between Forward-ME and UK Health and Social Care Information Centre
  • SNOMED CT retires Mental disorder parent for Chronic fatigue syndrome and ME
  • Projected changes to April 2016 release of Read Codes Clinical Terms Version 3 (CTV3)
  • Read Codes system to be phased out as part of wider SNOMED CT implementation

In addition to ICD-10, a number of terminology and electronic health and medical record systems are used in the UK in primary, secondary, and health and social care clinical settings, which include:

OPCS-4 (classification of Surgical Operations and Procedures)

SNOMED CT (Systematized Nomenclature of Medicine – Clinical Terms, a comprehensive, multilingual clinical terminology system)

Read Codes (a coded thesaurus of clinical terms for recording patient findings and procedures in health and social care IT systems across primary and secondary care, e.g. GP surgeries and reporting of pathology results).

The National Information Board (NIB) has specified that all primary care systems adopt SNOMED CT by the end of December 2016 and that SNOMED CT is to be used as the single terminology in all health care settings in England, with a projected adoption date for the entire health system of April 2020 [3].

You can access a public SNOMED CT browser here: IHTSDO browser

This is an online browser and does not require any software to be downloaded. You will need to accept the license and then select for the UK “Local Extension” of SNOMED CT. Click on the “Search” tab to enter clinical terms.

The SNOMED CT International Edition and “Local Extensions” for a number of other countries, including the US, are also available via the browser. All editions release new updates twice a year, on a staggered schedule. The Release schedule for the UK Extension is April and October.

Read Codes system to be retired

The Read Codes system of clinical terms has been used in the NHS since 1985. As part of the adoption of SNOMED CT in primary care, Clinical Terms Version 3 (CTV3) is being deprecated.

More information on the phasing out of Read Codes, here:

Retirement of Read Version 2 and Clinical Terms Version 3

Click link for PDF document Retirement Schedule

There was no new release for CTV3 issued in October, but the April 2016 release is scheduled for Friday, 18th March 2016. The last release of CTV3 will be published in April 2018.

How have CFS and related terms been listed within SNOMED CT and CTV3?


Prior to July 2015, all editions of SNOMED CT had the following listings for CFS, ME and PVFS:

Chronic fatigue syndrome (with ME – Myalgic encephalomyelitis and several other related and historical terms listed under Synonyms) was assigned two parent disorder classes: Mental disorder, and Multisystem disorder.

Postviral fatigue syndrome was listed under Children to Chronic fatigue syndrome.

Read Codes (CTV3)

The twice yearly Read Codes releases (April and October) are available only to license holders but the codes can be viewed through this public resource (caveat: it is unclear how often this NCBO BioPortal ontology resource is updated with new releases for individual ontology systems):

See: BioPortal Xa01F

For CTV3, Xa01F Chronic fatigue syndrome (with ME – Myalgic encephalomyelitis and PVFS – Postviral fatigue syndrome under Synonyms) is listed, hierarchically, under two parent disorder classes: as a Sub Class of both Neurasthenia, under parent: Mental health disorder, and as a Sub Class of Neurological disorder.

See: http://purl.bioontology.org/ontology/RCD/Xa01F

Mental health disorder > Neurotic disorder > Somatoform disorder > Neurasthenia > Chronic fatigue syndrome


Neurological disorder > Chronic fatigue syndrome

See also the Visualization tab for a diagrammatic representation of dual parentage:


Correspondence between Countess of Mar and UK Health and Social Care Information Centre

Forward-ME is an informal group for ME charities and voluntary organizations, chaired by the Countess of Mar, who also serves as Co-chair to the All-Party Parliamentary Group on Myalgic Encephalomyelitis (ME).

Between November 2014 and June 2015, Lady Mar was in correspondence with Mr Leon Liburd, Senior Support Analyst Systems and Service Delivery, and Ms Elaine Wooler, Advanced Clinical Terminology Specialist, UK Health and Social Care Information Centre.

Their correspondence (in reverse date order) was published on the Forward-ME website in June and can be read here Correspondence re SNOMED added June 2015

or open PDF here on Dx Revision Watch

Click link for PDF document  Correspondence re SNOMED

Changes to SNOMED CT

As a result of these exchanges, Lady Mar was advised that the relationship between the entry for 52702003 Chronic fatigue syndrome and the Mental disorder parent had been retired. In future editions, Chronic fatigue syndrome would be listed under the single parent, 281867008 Multisystem disorder.

See here

Additionally, 51771007 Postviral fatigue syndrome was being removed as a subtype of 52702003 Chronic fatigue syndrome (disorder) – though no rationale for this specific decision appears to be provided within the correspondence.

See here

[So 51771007 Postviral fatigue syndrome would be no longer be listed as a sub class under Children to 52702003 Chronic fatigue syndrome but directly under two parents: 281867008 Multisystem disorder and 123948009 Post-viral disorder.]

These changes were effected in the July 2015 release for the International Edition (Release 20150731).

They were subsequently incorporated into the September 2015 US Extension (Release 20150901), the October 2015 UK Extension (Release 20151001) and the November 2015 Swedish Extension (Release 20151130). It is expected that other country Extensions will also reflect these changes in their forthcoming releases.

Within the correspondence, on 11 November 2014, Mr Leon Liburd had also advised Lady Mar:

“It is also noted that the corresponding representation in the UK’s Clinical Terms Version 3 terminology product Xa01F | Chronic fatigue syndrome is classified as both a Neurological disorder and a Mental health disorder. As such, any conclusions emerging from the SNOMED CT discussions would also be reflected in the CTV3 UK product.”

Clarification re CFS and CTV3

In November, I contacted the UK Health and Social Care Information Centre for clarification of how CFS and its various Synonyms are currently listed within CTV3.

On 20 November, I was advised by Karim Nashar, Terminology Specialist, UK Terminology Centre, Health and Social Care Information Centre, that:

“[Xa01F | Chronic fatigue syndrome was being moved] under a single supertype 281867008 | Multisystem disorder (disorder) as to reflect the SNOMED correction in CTV3″

and that this change should be reflected in the April 2016 CTV3 release.

As noted above, Clinical Terms Version 3 (CTV3) is being deprecated and the last release of CTV3 will be published in April 2018.

The ICD-11 Beta draft and proposed classification of the G93.3 legacy terms

In June, WHO’s Dr Robert Jakob had told me that if TAG Neurology’s proposals and rationales for the G93.3 legacy terms were not ready for public release in September, he projected their release by December, latest (see towards end of Post #324).

No proposals were released in September and none in December. Eight years into the revision process and stakeholders still don’t know how ICD Revision proposes to classify the ICD-10 G93.3 legacy terms for ICD-11.

On 28 December, I called again, via the ICD-11 Beta Comments mechanism, for these terms to be restored to the public version of the Beta drafting platform.


1 UK Terminology Centre (UKTC): http://systems.hscic.gov.uk/data/uktc/

2 SNOMED CT: http://systems.hscic.gov.uk/data/uktc/snomed

3 NIB document ‘Personalised Health and Care 2020: A Framework for Action’:

4 IHTSDO browser: http://browser.ihtsdotools.org

5 Retirement of Read Version 2 and Clinical Terms Version 3: http://systems.hscic.gov.uk/data/uktc/readcodes

6 NCBO BioPortal Read Codes (CTV3) Xa01F Chronic fatigue syndrome

7 Forward-ME Correspondence re SNOMED added June 2015


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