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/


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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