I have been trying to get a better understanding of the development of the WHO ICD codes in relation to ME and CFS and although I haven't read it all am finding the document linked to on the Hummingbird site helpful. There is a long and short version. the contents of the long version are http://www.hfme.org/wlicdcodes.htm there are downloadable versions (Word or PDF) NOTE; the document is 10 years old and only goes up to 2009 so it is purely for historical reference. for the more recent changes see @Dx Revision Watch thread https://www.s4me.info/threads/updat...-classification-and-terminology-systems.3912/
Also see: History of coding of PVFS, BME and CFS in ICD to March 2001, CDC archived document: PDF: 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, CDC archive document, March 2001.
Note that towards the end of Page 2 of the CDC, 2001 document, it states: "ICD-10-CM "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..." This didn't happen. Although NCHS/CDC adopted the WHO's ICD-10 for mortality data in 1999, it took much longer for the U.S. to develop, test and implement a clinical modification of ICD-10 for morbidity use. NCHS/CDC released the first draft of ICD-10-CM for review in 2003. The ICD-10-CM 2003 draft had proposed the structure on the left of this image for the G93.3 terms. So the 2003 draft release saw the first proposal to include a "chronic fatigue syndrome NOS*" term under the ICD-10-CM Symptoms, signs chapter, as an inclusion under R53.82 Chronic fatigue, unspecified (neither of which term appears in the WHO's unmodified ICD-10 and nor does the term, "Chronic fatigue syndrome, postviral"**). *NOS = Not Otherwise Specified **Prof Peter White is mistaken in his assertion that these terms are coded in the WHO's ICD-10. Mary Schweitzer recounts that in 2004, she had attended a CFSAC meeting at which CDC's Donna Pickett and the late William Reeves were presenting. Dr Reeves had shown some slides which included ICD-10-CM draft proposals for the G93.3 terms. But one of his slides had showed a revised proposed structure to the draft release, as it had stood in 2003. Reeves had apparently argued, in 2004, that because ICD-10-CM proposed to have a "Chronic fatigue syndrome NOS" under R53.82, the "Chronic fatigue syndrome, postviral" under G93.3 was superfluous and should be removed. (At that point in time, proposing changes to the draft ICD-10-CM was not a public process. It did not become a public process until the 2010 C & M Committee meetings.) The revised structure on the right of the image is how the next draft release stood when it was published in 2007 and also how it stood when a further draft was released, in 2010. In 2015, when ICD-10-CM was finally implemented after several delays, it implemented with the revised 2007 structure. You'll note that for the 2007 release, the "chronic fatigue syndrome, postviral" term had been deleted from the proposed G93.3 hierarchy and the corresponding "postviral chronic fatigue (G93.3)" exclusion had been removed as an Excludes1 under the R53.82 code. The full PDFs of the draft ICD-10-CM Tabular List release for 2003 and for 2007 are archived on my site here: The ICD-10-CM 2003 draft release: https://dxrevisionwatch.files.wordpress.com/2015/03/icd-10-cm-draft-2003.pdf The ICD-10-CM 2007 draft release: https://dxrevisionwatch.files.wordpress.com/2015/03/2007-tabular-list-release.pdf No other clinical modification of the WHO's ICD-10 has "chronic fatigue syndrome" or "chronic fatigue syndrome NOS" located in the Symptoms, signs chapter R codes. Note that ICD-10-CM is also used used by Belgium, Luxembourg and in parts of Spain. ---------------------------------------------------------------- Incidentally, at the Beta drafting stage, the original list of around 16 Synonyms/Full index terms for ICD-11's 8E49 Postviral fatigue syndrome had also included the ICD-10-CM terms: chronic fatigue syndrome NOS chronic fatigue, unspecified even though these terms are not included in the WHO's ICD-10, were R chapter terms imported from, and unique to ICD-10-CM, and had been imported into the ICD-11 Beta draft at a time when the ICD-10-CM had yet to be implemented. WHO/ICD Revision later deleted the "chronic fatigue syndrome NOS" term voluntarily from the ICD-11 Beta draft. In January 2019, I submitted a proposal and rationale for the deletion of the "chronic fatigue, unspecified" term, which was accepted and WHO/ICD Revision deleted the term from the 8E49 Postviral fatigue syndrome Full index terms list on March 15, 2019. For ICD-11, chronic fatigue syndrome is an inclusion term under 8E49 Postviral fatigue syndrome in the ICD-11 equivalent of the Tabular List. It is currently unknown whether the WHO intends to grant licenses to Member States to develop clinical modifications of ICD-11. [Edited for clarity]