US “Clinical Modification” ICD-10-CM: Clarification

US “Clinical Modification” ICD-10-CM: Clarification


This post is intended to clarify any confusion between ICD-10, ICD-11 and the forthcoming US Clinical Modification of ICD-10 which will be known as ICD-10-CM.

The WHO published ICD-10 in 1992. The current version of ICD-10 (Version for 2007) is used in the UK and in many countries throughout the world.

ICD-10 is under revision and the development of the structure and content of ICD-11 has been underway since 2007. ICD-11 is scheduled for completion in 2014.


Clinical Modifications

Several countries are permitted to publish adaptations of the ICD called “Clinical Modifications” (sometimes known as “national modifications”).

Countries using Clinical Modifications of ICD-10 include Canada (ICD-10-CA), Australia (ICD-10-AM) and Germany (ICD-10-GM).

The United States currently uses an adaptation of the WHO’s now retired ICD-9, called ICD-9-CM, and has been slow to move onto ICD-10.

Rather than skip ICD-10 and move straight onto ICD-11 in 2014+, the US has been developing a modification of ICD 10 called ICD-10-CM which will replace ICD-9-CM.

ICD-10-CM is due for implementation in October 2013.

According to one report, the US should not expect to move on to ICD-11 (or a modification of ICD-11) until well after 2020, assuming that the ICD-11 Beta is published around the 2014-2015 projection:

Why move to ICD-10, if ICD-11 is on the horizon?


What are the proposed classifications and codings for PVFS, (Benign) ME and Chronic fatigue syndrome for ICD-10-CM?

In March 2001, the document:

“A Summary of Chronic Fatigue Syndrome and Its Classification in the International Classification of Diseases Prepared by the Centers for Disease Control and Prevention, National Center for Health Statistics, Office of the Center Director, Data Policy and Standards”

provided a concise “summary of the classification of Chronic Fatigue Syndrome in the International Classification of Diseases (ICD), ninth and tenth revisions, and their clinical modifications.”

That document is archived here:

In 2001, the proposal had been:

“In keeping with the placement in the ICD-10, chronic fatigue syndrome (and its synonymous terms) will remain at G93.3 in ICD-10-CM.”

So at that point, it was being proposed for the forthcoming US ICD-10-CM that PVFS, (Benign) ME and Chronic fatigue syndrome would be coded at G93.3, which would have placed all three terms in Chapter VI: Diseases of the nervous system (the Neurological chapter).

But the current proposals for ICD-10-CM propose classifying Chronic fatigue syndrome in Chapter 18, under R53 Malaise and fatigue, at R53.82.

The “R” codes are classified under

Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99)

This chapter includes symptoms, signs, abnormal results of clinical or other investigative procedures, and ill defined conditions regarding which no diagnosis classifiable elsewhere is recorded…

Note: this is not the ICD-10-CM Mental and Behavioural chapter, which is:

Mental and behavioral disorders (F01-F99)
Includes: disorders of psychological development
Excludes2: symptoms, signs and abnormal clinical laboratory findings, not elsewhere classified (R00-R99)

which specifically excludes the R00-R99 codes.

So the current proposal for ICD-10-CM separates CFS and Postviral fatigue syndrome into mutually exclusive categories:

“Chronic fatigue, unspecified” and “Chronic fatigue syndrome not otherwise specified” appear in Chapter 18, under R53 Malaise and fatigue, at R53.82.

Whilst “Postviral fatigue syndrome” and “benign myalgic encephalomyelitis” appear in Chapter 6, under G93 Other disorders of brain, at G93.3.

At some point before October 2013, ICD-10-CM revision will be “frozen” for Centers for Medicare and Medicaid Services (CMS) and insurance companies to prepare for the October 1, 2013 implementation.

See Tom Sullivan at ICD10 (no connection with my site) here:

CMS, CDC call for ICD-9 and ICD-10 code freeze

“CMS, the Centers for Medicare and Medicaid Services, along with CDC, the Centers for Disease Control and Prevention, proposed that both ICD-9-CM and ICD-10-CM/PCS code sets be frozen two years before the compliance deadline.

“What that means: As of October 1, 2011, only limited updates would be instituted into the code sets so that providers, payers, clearinghouses, and health IT vendors, will not have to simultaneously keep pace with code updates while also reconfiguring their existing systems for ICD-10-CM/PCS.” ICD10

During the last ten minutes of the CFSAC meeting on Monday, 10 May, Dr Lenny Jason raised his concerns with the committee that the placement of CFS in ICD-10-CM in the Chapter 18 “R” codes could be problematic.

Videocast of full CFSAC meeting here:

In August 2005, CFSAC had submitted the following recommendation to the Secretary:

“Recommendation 10: We would encourage the classification of CFS as a ‘Nervous System Disease,’ as worded in the ICD-10 G93.3.”

I suggest that US advocates with concerns about current proposals for the placement of CFS within ICD-10-CM keep a close eye on decisions about the date by which ICD-10-CM is to be frozen.

For the most recent ICD-10-CM proposals see:

The 2010 update of ICD-10-CM is now available and replaces the July 2009 version.

The file for the Tabular List is in a Zipped file which is not that easy to locate on the site. A non Zipped PDF can be downloaded from this site:

or open the PDF on my Dx Revision Watch site, here


Tabular List of Diseases and Injuries Page 1165 (Update for 2010)

R53 Malaise and fatigue


R53.8 Other malaise and fatigue

Excludes1: combat exhaustion and fatigue (F43.0)
congenital debility (P96.9)
exhaustion and fatigue due to:
depressive episode (F32.-)
excessive exertion (T73.3)
exposure (T73.2)
heat (T67.-)
pregnancy (O26.8-)
recurrent depressive episode (F33)
senile debility (R54)

R53.81 Other malaise

Chronic debility
Debility NOS
General physical deterioration
Malaise NOS
Nervous debility
Excludes1: age-related physical debility (R54)

R53.82 Chronic fatigue, unspecified

Chronic fatigue syndrome NOS
Excludes1: postviral fatigue syndrome (G93.3)

R53.83 Other fatigue

Fatigue NOS
Lack of energy


ICD-10-CM CHAPTER 6 Page 325 (Update for 2010)

Diseases of the nervous system (G00-G99)


symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)


G93 Other disorders of brain


G93.3 Postviral fatigue syndrome

Benign myalgic encephalomyelitis
Excludes1: chronic fatigue syndrome NOS (R53.82)

For comparison:

German Modification ICD-10-GM

ICD-10-GM Version 2010

Kapitel VI
Krankheiten des Nervensystems

G93.- Sonstige Krankheiten des Gehirns


G93.3 Chronisches Müdigkeitssyndrom

Benigne myalgische Enzephalomyelitis
Chronisches Müdigkeitssyndrom bei Immundysfunktion
Postvirales Müdigkeitssyndrom

For comparison:

Canadian Modification ICD-10-CA

(Version 2009 of ICD-10-CA/CCI replaces version 2006)

Version 2009 ICD-10-CA Tabular List, Volume 1 PDF (4.9MB)

Version 2009 ICD-10-CA Alphabetical Index, Volume 2 PDF (4.3MB)

Chapter VI

Diseases of the nervous system

Other disorders of the nervous system


G93 Other disorders of brain


G93.3 Postviral fatigue syndrome

Includes: Benign myalgic encephalomyelitis
Chronic fatigue syndrome

Excludes: fatigue syndrome NOS (F48.0)

For comparison with WHO ICD-10:

Current ICD-10 codings for the three terms are set out on my site, here, together with extracts from Chapter V (the “F” codes) and Chapter XVIII (the “R” codes):

or go here for the full ICD-10 Volume 1: Tabular List

ICD-10 Version for 2007 online

Chapter VI

Diseases of the nervous system

Other disorders of the nervous system


G93 Other disorders of brain


G93.3 Postviral fatigue syndrome
Benign myalgic encephalomyelitis

Note that in ICD-10, Chronic fatigue syndrome is not included in Volume 1: The Tabular List, Chapter VI under the parent term:

G93 Other Disorders of brain

but “Chronic fatigue syndrome” does appear in Volume 3: The Alphabetical Index, where it is indexed to G93.3.

In a forthcoming post, I shall be publishing important information about proposals for parent terms, classifications and codings in the ICD-11 Alpha Draft.


Related material:


For information on the current codings in ICD-9-CM (US Clinical Modification) see the NAME U.S. page: WHO ICD Codes section

American Psychiatric Association on DSM-5

In a 10 December Press Release, the American Psychiatric Association said:

“Extending the timeline [for DSM-5] will allow more time for public review, field trials and revisions”


“The extension will also permit the DSM-5 to better link with the U.S. implementation of the ICD-10-CM codes for all Medicare/Medicaid claims reporting, scheduled for October 1, 2013. Although ICD-10 was published by the WHO in 1990, the “Clinical Modification” version (ICD- 10-CM) authorized by the U.S. Centers for Medicare and Medicaid Services (CMS) and the Centers for Disease Control (CDC) is not being implemented in the U.S. until 23 years later.

“The ICD-10-CM includes disorder names, logical groupings of disorders and code numbers but not explicit diagnostic criteria. The APA has already worked with CMS and CDC to develop a common structure for the currently in-use DSM-IV and the mental disorders section of the ICD- 10-CM.

“The International Classification of Diseases (ICD) is published by the WHO for all member countries to classify diseases and medical conditions for international health care, public health, and statistical use. The WHO plans to release its next version of the ICD, the ICD-11, in 2014.

“APA will continue to work with the WHO to harmonize the DSM-5 with the mental and behavioral disorders section of the ICD-11. Given the timing of the release of both DSM-5 and ICD-11 in relation to the ICD-10-CM, the APA will also work with the CDC and CMS to propose a structure for the U.S. ICD-10 CM that is reflective of the DSM-5 and ICD-11 harmonization efforts. This will be done prior to the time when the ICD-10-CM revisions are “frozen” for CMS and insurance companies to prepare for the October 1, 2013, adoption.”