ICD-10 General Coding Rules and Conventions

Question 1

What is DRule.1 called?

Answer 1

Axis of the classification

Question 2

What does DRule.1 state?

Answer 2

Where there is any doubt as to where a condition should be coded, the special group chapters must take priority.

Question 3

What kind of classification is ICD-10?

Answer 3

Variable-axis

Question 4

What are the three types of chapter in ICD-10?

Answer 4

Special Group
Body System
Other

Question 5

Which chapters are Special Group Chapters?

Answer 5

I-V, XV-XVII, XIX

Question 6

Which chapters are Other Chapters?

Answer 6

XVIII, XX-XXII

Question 7

Which chapters are Body System Chapters?

Answer 7

VI-XIV

Question 8

What does DRule.2 state?

Answer 8

Code assignment must always be made to four or five character level (where available and in line with fifth character coding standards), for the code to be valid.

Where a three character category code is not subdivided into four character subdivisions the ‘X’ filler must be assigned in the fourth character field so the codes are of a standard length for data processing and validation. The code is still considered a three character code from a classification perspective.

Where a three character code requires assignment of both the ‘X’ filler and a fifth character subdivision, the ‘X’ filler must continue to be recorded in the fourth field before the fifth character.

Question 9

What is the purpose of the filler .X 4th character?

Answer 9

It ensures all codes are of a standard length for data processing and validation.

Question 10

What is DRule.2 called?

Answer 10

Category and code structure

Question 11

What is DConvention.1 called?

Answer 11

Cross references

Question 12

What does DConvention.1 state?

Answer 12

Cross references are provided in the Alphabetical Index to ensure that all possible terms or its synonyms are referenced by the coder. Cross references explicitly direct the coder to other entries in the index:

See - This is an explicit direction to look elsewhere as no codes can be found alongside this cross reference. It is used to direct the coder to another lead term in the Alphabetical Index where complete information can be found. It is also used after anatomical sites to remind the coder that the Alphabetical Index is organised by condition.

See also - This is a reminder to look under another lead term if the term the coder is looking for cannot be found modified in any way under the first lead term.

Question 13

What are the 2 cross references in ICD-10?

Answer 13

See and see also

Question 14

How is ‘see’ used as a cross reference in ICD-10?

Answer 14

‘See’ is an explicit direction to look elsewhere as no codes can be found alongside this cross reference.

It is used to direct the coder to another lead term in the Alphabetical Index where complete information can be found.

It is also used after anatomical sites to remind the coder that the Alphabetical Index is organised by condition.

Question 15

How is ‘see also’ used as a cross reference in ICD-10?

Answer 15

‘See also’ is a reminder to look under another lead term if the term the coder is looking for cannot be found modified in any way under the first lead term.

Question 16

What is DConvention.2 called?

Answer 16

Instructional notes

Question 17

What does DConvention.2 state?

Answer 17

Instructional ‘Notes’ are used within the Tabular list at chapter, block, three-character and four-character levels. They describe the general content of the succeeding categories, give instruction regarding the use of categories and provide fifth character subclassifications.

Inclusion notes (inclusion terms, ‘Incl.:’) clarify the content and intended use of the chapter, block, category or subcategory to which the notes apply. They give examples of the conditions and diagnoses classified at the chapter, block, category or code. The listed inclusion terms are not exhaustive and alternative diagnoses are listed in the Alphabetical Index. Inclusion notes appearing under chapter and block titles usually give a general definition of the content of the section to which they apply. These inclusion notes apply to all categories within the chapter or block. Inclusion notes at four character code level are not preceded by the abbreviation Incl.:

Exclusion notes (exclusion terms, ‘Excl.:’) are used to prevent a category or code from being used incorrectly. They inform the coder that, although the category or code description may suggest the term could be classified here, it is in fact classified elsewhere. They do not always prevent the use of the code from the category the exclusion note appears in; they can indicate that a code from a different category should be assigned in addition to fully reflect the patient’s diagnoses.

Use notes are a specific instruction to use an additional code in order to describe a condition more completely. The ‘use’ note is never optional and must always be adhered to where the information is available in the medical record.

Where a note states to ‘Use an additional code, if desired’ to add further information about the disorder, where that information is present in the medical record the additional code must be assigned.

Where a note contains the phrase ‘are for use with’, this instruction is mandatory, and the four-character subdivisions referred to must be used.

Question 18

Where can instructional notes be found in ICD-10?

Answer 18

At chapter, block, three-character and four-character levels.

Question 19

How are ‘inclusion’ notes displayed and used in ICD-10?

Answer 19

Inclusion notes (inclusion terms, ‘Incl.:’) clarify the content and intended use of the chapter, block, category or subcategory to which the notes apply. They give examples of the conditions and diagnoses classified at the chapter, block, category or code.

The listed inclusion terms are not exhaustive and alternative diagnoses are listed in the Alphabetical Index. Inclusion notes appearing under chapter and block titles usually give a general definition of the content of the section to which they apply. These inclusion notes apply to all categories within the chapter or block.

Inclusion notes at four character code level are not preceded by the abbreviation Incl.:

Question 20

How are ‘exclusion’ notes displayed and used in ICD-10?

Answer 20

Exclusion notes (exclusion terms, ‘Excl.:’) are used to prevent a category or code from being used incorrectly. They inform the coder that, although the category or code description may suggest the term could be classified here, it is in fact classified elsewhere.

They do not always prevent the use of the code from the category the exclusion note appears in; they can indicate that a code from a different category should be assigned in addition to fully reflect the patient’s diagnoses.

Question 21

What are the different forms of notes found in ICD-10?

Answer 21

Inclusion
Exclusion
Use
If desired
Are for use with

Question 22

How are ‘Use’ notes displayed and used in ICD-10?

Answer 22

Use notes are a specific instruction to use an additional code in order to describe a condition more completely. The ‘use’ note is never optional and must always be adhered to where the information is available in the medical record.

Question 23

How are ‘If desired’ notes displayed and used in ICD-10?

Answer 23

Where a note states to ‘Use an additional code, if desired’ to add further information about the disorder, where that information is present in the medical record the additional code must be assigned.

Question 24

How are ‘are for use with’ notes displayed and used in ICD-10?

Answer 24

Where a note contains the phrase ‘are for use with’, this instruction is mandatory, and the four-character subdivisions referred to must be used.

Question 25

What is DConvention.3 called?

Answer 25

Punctuation

Question 26

What forms of punctuation are used in ICD-10?

Answer 26

Braces
Square brackets
Colons
Point dashes
Parentheses

Question 27

What does DConvention.3 state?

Answer 27

Braces (indicated by a vertical line in the Tabular List) are used in inclusion and exclusion notes to indicate that both the listed condition and one of its modifiers must be present in order to complete the instruction. Braces enclose a series of terms, modified by the statement appearing at the right of the brace.

Square brackets are used to:
- enclose synonyms, alternative words, or explanatory phrases
- enclose an instruction to ‘see’ previously listed subdivisions common to a number of categories
- refer to a previous ‘see’ note.

A colon is used above a list of bulleted modifiers in the Tabular List. The word preceding the colon must be followed by one of the bulleted modifiers in order for that code to be assigned.

A point-dash is used in both the Tabular List and the Alphabetical Index to indicate there are fourth character subdivisions.

Parentheses are used to enclose nonessential modifiers. They are also used to enclose chapters, categories and codes listed in instructional notes, code ranges in block titles and dagger or asterisk codes in the Tabular List and to enclose cross-reference terms in the Alphabetical Index.

Question 28

How are braces used in ICD-10?

Answer 28

Braces (indicated by a vertical line in the Tabular List) are used in inclusion and exclusion notes to indicate that both the listed condition and one of its modifiers must be present in order to complete the instruction. Braces enclose a series of terms, modified by the statement appearing at the right of the brace.

Question 29

How are square brackets used in ICD-10?

Answer 29

Square brackets are used to:
- enclose synonyms, alternative words, or explanatory phrases
- enclose an instruction to ‘see’ previously listed subdivisions common to a number of categories
- refer to a previous ‘see’ note.

Question 30

How are colons used in ICD-10?

Answer 30

A colon is used above a list of bulleted modifiers in the Tabular List. The word preceding the colon must be followed by one of the bulleted modifiers in order for that code to be assigned.

Question 31

How are point dashes used in ICD-10?

Answer 31

A point-dash is used in both the Tabular List and the Alphabetical Index to indicate there are fourth character subdivisions.

Question 32

How are parentheses used in ICD-10?

Answer 32

Parentheses are used to enclose nonessential modifiers. They are also used to enclose chapters, categories and codes listed in instructional notes, code ranges in block titles and dagger or asterisk codes in the Tabular List and to enclose cross-reference terms in the Alphabetical Index.

Question 33

What is DConvention.4 called?

Answer 33

Abbreviations

Question 34

What does DConvention.4 State?

Answer 34

NOS - Not Otherwise Specified. A term without any essential modifier is usually the unspecified form of the condition. The code assignment is that which directly follows the lead term in the Alphabetical Index. When the clinician states a diagnosis, problem or reason for an encounter as a single term which has no modifiers, in classification terms it is said to be ‘unspecified’ or unqualified or NOS. The coder must ensure there is no further information in the medical record that would allow for the assignment of a more specific code.

NEC - Not Elsewhere Classified. Assignment of a tentative code which uses NEC should be avoided if at all possible. The category for the term including NEC is to be used only when the coder lacks the information necessary to code the term to a more specific category. The phrase ‘not elsewhere classified’ is used in the Tabular List for residual categories to indicate that other specified variants of the condition may appear in other parts of the classification. Often, but not always, an exclusion note appears in an ‘NEC’ category, directing the coder to the code range, category or four character code where the condition is classified.

Question 35

How is NOS (not otherwise specified) used in ICD-10?

Answer 35

A term without any essential modifier is usually the unspecified form of the condition. The code assignment is that which directly follows the lead term in the Alphabetical Index.

When the clinician states a diagnosis, problem or reason for an encounter as a single term which has no modifiers, in classification terms it is said to be ‘unspecified’ or unqualified or NOS. The coder must ensure there is no further information in the medical record that would allow for the assignment of a more specific code.

Question 36

How is NEC (not elsewhere classified) used in ICD-10?

Answer 36

Assignment of a tentative code which uses NEC should be avoided if at all possible. The category for the term including NEC is to be used only when the coder lacks the information necessary to code the term to a more specific category.

The phrase ‘not elsewhere classified’ is used in the Tabular List for residual categories to indicate that other specified variants of the condition may appear in other parts of the classification. Often, but not always, an exclusion note appears in an ‘NEC’ category, directing the coder to the code range, category or four character code where the condition is classified.

Question 37

What is DConvention.5 called?

Answer 37

Relational Terms

Question 38

What relational terms are used in ICD-10?

Answer 38

And
With
Without
In
Due to
Resulting in

Question 39

What does DConvention.5 state?

Answer 39

‘And’ within code descriptions means and/or. It indicates that the code can be assigned if either one or both elements within the code description are present.

‘With’ is used either when two or more conditions combine to form another condition or to provide additional four character specificity. These terms indicate that both elements in the code description must be present in the diagnostic statement in order to assign the code. These terms do not necessarily indicate a cause-effect relationship. ‘With’ always appears first in the list of modifiers in the Alphabetical Index.

‘Without’ indicates that the named element must not be present in the diagnostic statement in order to assign the code.

‘In, due to and resulting in’ indicate a causal relationship between the elements in the title and requires the responsible consultant to confirm a cause-effect relationship within the medical record before the code(s) can be assigned. This may be clear from the diagnostic statement or in the combinations of conditions. In other instances, ICD-10 presumes a relationship unless otherwise qualified. These terms are usually used where a condition only occurs because of the presence of another condition. ‘In’ and ‘due to’ are used interchangeably as they have the same meaning, and in many cases appear as ‘in (due to)’. In the vast majority of cases, the subentries have both dagger and asterisk codes. ‘In’ and ‘due to’ are also used in other situations such as ‘in pregnancy’ or ‘due to drugs’.

Question 40

What does the relational term ‘and’ mean in ICD-10?

Answer 40

‘And’ within code descriptions means and/or. It indicates that the code can be assigned if either one or both elements within the code description are present.

Question 41

What does the relational term ‘with’ mean in ICD-10?

Answer 41

‘With’ is used either when two or more conditions combine to form another condition or to provide additional four character specificity.

These terms indicate that both elements in the code description must be present in the diagnostic statement in order to assign the code. These terms do not necessarily indicate a cause-effect relationship.

‘With’ always appears first in the list of modifiers in the Alphabetical Index.

Question 42

What does the relational term ‘without’ mean in ICD-10?

Answer 42

‘Without’ indicates that the named element must not be present in the diagnostic statement in order to assign the code.

Question 43

What do the relation terms ‘in’, ‘due to’ and ‘resulting in’ mean in ICD-10?

Answer 43

‘In, due to and resulting in’ indicate a causal relationship between the elements in the title and requires the responsible consultant to confirm a cause-effect relationship within the medical record before the code(s) can be assigned. This may be clear from the diagnostic statement or in the combinations of conditions. In other instances, ICD-10 presumes a relationship unless otherwise qualified.

These terms are usually used where a condition only occurs because of the presence of another condition. ‘In’ and ‘due to’ are used interchangeably as they have the same meaning, and in many cases appear as ‘in (due to)’. In the vast majority of cases, the subentries have both dagger and asterisk codes.

‘In’ and ‘due to’ are also used in other situations such as ‘in pregnancy’ or ‘due to drugs’.

Question 44

What is DConvention.6 called?

Answer 44

Modifiers

Question 45

What does DConvention.6 state?

Answer 45

Modifiers are also referred to as qualifiers and are descriptive words used to further describe or modify a diagnosis. They are found in the Alphabetical Index and the Tabular List.

Nonessential modifiers are supplementary words and descriptors which do not affect the code selection for a given diagnosis. These modifiers may be present or absent in the diagnostic statement but result in the assignment of the same code. They appear in parentheses following the terms they modify.

Essential modifiers are descriptive terms which do affect the code selection for a given diagnosis. These modifiers describe essential differences (for the purpose of coding) in site, aetiology, or type of disorder. These terms must appear in the diagnostic statement for the code to be assigned. Essential modifiers appear as subterms indented below lead terms. Each indented list is in alphabetical order, with the following exceptions:
- Whenever the relational term ‘with’ is used it is always the first entry of the indented list
- Numbers listed as Arabic numbers appear at the end of the list after all the modifying words in numeric order
- Numbers listed as Roman numerals appear in numeric order

Question 46

What are modifiers in ICD-10 and what types are found?

Answer 46

Modifiers are also referred to as qualifiers and are descriptive words used to further describe or modify a diagnosis. They are found in the Alphabetical Index and the Tabular List.

Two forms are found in ICD-10; essential and nonessential.

Question 47

What are nonessential modifiers in ICD-10 and how do they appear?

Answer 47

Nonessential modifiers are supplementary words and descriptors which do not affect the code selection for a given diagnosis. These modifiers may be present or absent in the diagnostic statement but result in the assignment of the same code.

They appear in parentheses following the terms they modify.

Question 48

What are essential modifiers in ICD-10 and how do they appear?

Answer 48

Essential modifiers are descriptive terms which do affect the code selection for a given diagnosis. These modifiers describe essential differences (for the purpose of coding) in site, aetiology, or type of disorder.

These terms must appear in the diagnostic statement for the code to be assigned. Essential modifiers appear as subterms indented below lead terms.

Each indented list is in alphabetical order, with the following exceptions:
- Whenever the relational term ‘with’ is used it is always the first entry of the indented list
- Numbers listed as Arabic numbers appear at the end of the list after all the modifying words in numeric order
- Numbers listed as Roman numerals appear in numeric order

Question 49

What is DConvention.7 called?

Answer 49

Fifth characters

Question 50

What does DConvention.7 state?

Answer 50

Supplementary fifth characters are used in Chapters IX, X, XIII and XIX to add greater specificity to the codes. Fifth characters activity codes are also available in Chapter XX but these codes are not to be used for national collection.

Question 51

Which chapters contain 5th characters?

Answer 51

Chapter IX - Diseases of the Circulatory System

Chapter X - Diseases of the Respiratory System

Chapter XIII - Diseases of the Musculoskeletal System and Connective Tissue

Chapter XIX - Injury, Poisoning and Certain Other Consequences of External Causes