WHO Wanted ICD-11, Part 2April 27, 2019
Now that you have an understanding of the WHO, and the rationale and benefits of transitioning to ICD-11, let’s take a look at the ICD-11 itself.
The WHO Overview of ICD-11
Here is a link to an ICD-11 Reference Guide, which is comprised of three parts.
- Part 1: An Introduction to ICD-11
- Part 2: Using ICD-11
- Part 3: New in ICD-11
Part 1 is self-explanatory.
Part 2 is comprised of 23 subsections and incudes explanation of the ICD-11 Code Structure, as follows:
2.2.1 Code structure
The codes of ICD–11 are alphanumeric and cover the range from 1A00.00 to ZZ9Z.ZZ. Codes starting with ‘X’ indicate an extension code (see Section 2.5 ‘Extension Codes’). The inclusion of a forced number at the third character position prevents spelling ‘undesirable words’. The letters ‘O’ and ‘I’ are omitted to prevent confusion with the numbers ‘0’ and ‘1’. Technically, the coding scheme would be described as below:
- E corresponds to a ‘base 34 number’ (0-9 and A-Z; excluding O, I);
- D corresponds to ‘base 24 number’ (A-Z; excluding O, I); and
- 1 corresponds to the ‘base 10 integers’ (0-9)
- The first E starts with ‘1’ and is allocated for the chapter. (i.e. 1 is for the first chapter, 2: chapter 2, A chapter 10, etc.)
The terminal letter Y is reserved for the residual category ‘other specified’ and the terminal letter ‘Z’ is reserved for the residual category ‘unspecified.’ For the chapters that have more than 240 blocks, ‘F’ (‘other specified’) and ‘G’ (‘unspecified’) are also used to indicate residual categories (due to problems with the coding space).
Chapters are indicated by the first character. For example, 1A00 is a code in chapter 1, and BA00 is a code in chapter 11.
Blocks are not coded within this code structure – each has its own. However, hierarchical relations are retained in the four-digit codes. There is unused coding space allocated in all blocks to allow for later updates and to keep the codes stable.
In Other Words…
ICD-11 codes are alphanumeric and range from 1A00.00 to ZZ9Z.ZZ. Note that the “dot” or “decimal” follows the fourth character, not the third character as in ICD-10.
There are no ICD-11 codes that begin with the letters “O” or “I.” Let’s take a look at two currently familiar and frequently coded examples of two common diagnoses and what the codes and code descriptors are in ICD-10-CM and ICD-11.
“Essential hypertension” is coded
- ICD-10-CM: I10 Essential (primary) hypertension
- ICD-11: BA00.Z Essential hypertension
Note that the code descriptors are close enough to be recognizable but are not identical.
The Tabular entry in the ICD-11 has an inclusion note, “hypertension NOS.” So we also see in this code example that many of the familiar abbreviations and conventions we are accustomed to in ICD-10-CM have been carried over to ICD-11.
“Normal spontaneous vaginal delivery”
- ICD-10-CM: O80 Encounter for full-term uncomplicated delivery in ICD-10-CM
- ICD-11: ZB20.Z Single spontaneous delivery, unspecified.
Note that the ICD-11 code descriptor does not include the term “full-term,” but does include the terms “single” and “spontaneous.” An inclusion term “uncomplicated delivery” is present in the Tabular.
Chapters are indicated by the first character and all codes in the same chapter will begin with the same character, either a letter or a number. There are 27 chapters in ICD-11. For chapters 1 through 9 the first character in the code is a number and indicates, or corresponds with, the chapter number. For example, code 1G40 Sepsis , are codes in chapter 1 (combination codes in ICD-11). Code 2E904 Benign neoplasm of tonsil, is a code in chapter 2.
For chapters 10 – 27, the first character is a letter, beginning with the letter A. For example, code AB31.0 Meniere disease is a code in chapter 10 and BA40.0 Unstable angina is a code in chapter 11.
“X” codes in ICD-11 are called Extension codes. See 2.33.27 Section X – Extension Codes, for which this information is currently provided:
“This chapter is new. Extension codes are envisaged as providing the basis for post-coordination of ICD–11 codes, being the repository for all codes in a linearization that are not eligible for use as stem codes. This mechanism is clearly envisaged for use with the morbidity linearization, and in that context mandatory (i.e. required) post-coordination can be accommodated. The role of Extension codes and post-coordination in the context of the mortality linearization is less clear, and the provision for mandatory post-coordination of Extension codes dimensions in the mortality linearization has been judged to be unlikely.”
AHIMA coding expert Sue Bowman, MJ, RHIA, CCS, FAHIMA, explained that “Extension codes cover additional information such as severity, more specific anatomic detail, and whether a condition was present on admission or not [this isn’t the complete list of the types of information extension codes cover, just examples]. It will be up to individual countries to decide to what extent they will use these extension codes.”
We anticipate that more information and explanations geared towards coders as well as statisticians and programmers will be forthcoming as time goes on. The process is explained in Part 3 New in ICD-11, and includes a section with subsections regarding Updating and Maintenance, 3.8.1 – 3.8.7.
Recommended reading and information specifically concerning implementation is explained and outlined by The Centers for Disease Control and Prevention/National Centers for Health Statistics in a Power Point presentation dated September 12, 2018, “Update on ICD-11: The WHO Launch and Implications for U.S. Implementation.”
More Chapters, More Codes, Rationales for Changes
There are 27 chapters in ICD-11. That’s six more chapters than in ICD-10-CM. A list of the ICD-11 chapters can be found in the Reference Guide Section 2.33 Chapter Structure of the ICD-11 MMS.
“ICD–11 has five new chapters. As a result, the numbering of the chapters has changed. The new chapters are:
- Chapter 03 Diseases of the blood or blood-forming organs and Chapter 04 – Disorders of the immune system. Conditions affecting the immune system and conditions affecting the blood are now in two separate chapters.
- Chapter 07 Sleep-Wake disorders. Sleep wake disorders have been regrouped in this new chapter.
- Chapter 17 Conditions related to sexual health. Sexual conditions have been grouped in this new chapter.
- Chapter 27 Traditional Medicine. A chapter for traditional medicine has been added.”
Here are two examples of Rationales pertaining to two chapters, one “old” and one “new.”
2.33.2 Chapter 02 – Neoplasms
220.127.116.11 Chapter 02 – Rationale for Chapter 02
The progress in oncology has clearly demonstrated that a site-only based categorization of malignant and benign tumors provides limited information for prevention, treatment, and prognosis for persons are affected by a tumor. ICD–10 had already included some categories based on histopathology (e.g. some lymphoid neoplasms).
In ICD–11, main tumor sites have subdivisions of histopathology first. The groups chosen were based on an analysis of international mortality and morbidity reporting, cancer registries, and clinical reporting. The redesigned sections were reviewed for missing details in relation to the ICD use cases.
Keeping the main anatomical axes intact allows backwards compatibility. However, the structure was adjusted in a few places to match anatomical subdivisions of the TNM classification.
For tumors of the central nervous system, the histological and behavioral distinction between benign and malignant is a grey area. As such, it was decided to move all central nervous system tumors outside the basic framework of behavior and group them together.
The field of genetic markers is rapidly changing. Whereas for some tumors, such markers have been used for many years, for others, this is not the case. As such, with the exception of hematological tumors, genetic markers were not included, and have not been used for the classification. They are, however, included in section ‘Extension codes’, and can be added as post coordination to the relevant code from the neoplasms chapter to fully describe the relevant tumor entity.
2.33.7 Chapter 07 – Sleep–wake disorders
18.104.22.168 Chapter 07 – Rationale for Chapter 07
As sleep-wake disorders pertain to an area of overlap between mental health, neurological disorders and pulmonary conditions, the decision was made to place them together in one chapter.
Examples of ICD-11 Codes and Descriptions (NOT from the final version or ICD-11-CM, neither of which currently exist)
Here are just a few examples from most of the chapters in ICD-11, obtained by using the Browser tool. You will see some new combination codes, some familiar and unfamiliar code descriptions. Applicable details of laterality and neoplasm morphology of neoplasms may not always appear during the search using this tool.
As mentioned, the codes in chapters 1 – 9 begin with a number, and the codes from chapter 10 on begin with an alpha character. The period appears after the fourth character. All ICD-11 codes are at a minimum of four (4) characters in length.
1B52.0 Streptococcal toxic shock syndrome
1B52.1 Staphylococcal toxic shock syndrome
2E05.0 Malignant neoplasm metastasis in ovary
3A71.0 Anemia in neoplastic disease
4B00.01 Acquired neutropenia
5A24 Uncontrolled or unstable diabetes mellitus
5A21.1 Hypoglycemia in the context of diabetes with coma
6C50.1 Gambling disorder, predominantly online
6C50.0 Gambling disorder, predominantly offline
7A00 Chronic insomnia
8A00.3 Functional parkinsonism
9C61.14 Acute angle closure with pupillary block
AB14 Acute myringitis
BA41.1 Acute non-ST elevation myocardial infarction
CB41.00 Acute respiratory failure, Type I (includes hypoxic)
DD70.1 Crohn disease of small intestine
EA90.0 Plaque psoriasis
FA80.9 Intervertebral disc degeneration of lumbar spine with prolapsed disc
GB61.5 Chronic kidney disease, stage 5
GB60.0 Acute kidney failure, stage 1
GB60.1 Acute kidney failure, stage 2
GB60.2 Acute kidney failure, stage 3
HA60 Gender incongruence of adolescence or adulthood
- NOTE: No codes beginning with character “I”
JB0D.6 Vaginal delivery following previous caesarean section
KA21.48 Preterm newborn, gestational age 36 completed weeks
LA8E.1 Atrial septal defect within oval fossa
MB45.Z Lack of coordination, unspecified
- NOTE: No codes beginning with character “O’
PC95 Intentional self-harm by exposure to or harmful effects of antidepressants
QA70 Overdose of substance without injury or harm
In summary, ICD-11-CM is years away from implementation in the US. Efforts are being made to ensure a smoother transition from ICD-10-CM to ICD-11-CM as compared to the transition from ICD-9-CM to ICD-10-CM. As noted throughout this blog, much information available now and going forward can be obtained from the WHO websites and links. More information from WHO, the Center for Medicare and Medicaid Services (CMS) and the National Committee for Health and Vital Statistics (NCHVS) will likely be available after ICD-11 is presented to the World Health Assembly in May 2019.
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