For internal use only, by 5th year medical students of the Dept of

Family Medicine of the University of Pretoria - 2004

ICD-10International Statistical

Classification of Diseases and Health Related Problems

– Tenth Revision – developed by the World

Health Organisation

ICD-10 codes used by permission of WHO, from: International Statistical Classification of Diseases

and Related Health Problems, Tenth Revision

ICD-10

International Statistical Classification of Diseases and Health Related Problems – Tenth Revision – developed by

the World Health Organisation

1. Purpose and applicability

A classification of diseases can be defined as a system of categories to which morbid entities are assigned according to established criteria.

The purpose of ICD is to establish a systematic recording, analysis, interpretation and comparison of morbidity and mortality data collected in different countries or areas and at different times.

The ICD is used to translate diagnoses of diseases and other health problems from words into an alphanumeric code, which permits easy storage, retrieval and analysis of the data.

In practice the ICD has become the international standard diagnostic classification for all general epidemiological and other health management purposes.

The ICD can be used to classify diseases and other health problems recorded on many types of health and vital records.

The original use of ICD was to classify causes of mortality as recorded in the register of death.

Later, the scope of ICD was extended to include diagnoses in morbidity.

Although ICD is primarily designed for the classification of diseases and injuries with a formal diagnosis, not every problem or reason for coming into contact with health services can be categorised this way.

Consequently, the ICD provides for a wide variety of signs, symptoms, abnormal findings, complaints, and social circumstances that may stand in place of a diagnosis on health-related records.

ICD can therefore be used to classify data recorded under headings such as

“diagnosis” e.g. C16.1: Malignant neoplasm of fundus of stomach;

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“reason for admission” e.g. R10.0: Acute abdomen - severe and generalised abdominal pain with abdominal rigidity;

“conditions treated” e.g. K56.6: Other and unspecified intestinal obstruction – enterostenosis; occlusion or stricture; or R18: Ascites;

“reason for consultation” e.g. R11: Nausea and vomiting

Data recorded under headings as the examples above, will

appear on a variety of health records from which statistics and other health-related information can be derived.

2. The importance and benefits of coding

The quality and integrity of data is increasingly becoming important in the health care industry as health information management evolves from record management to data management. Worldwide coding systems form an essential part of the health information system.

Coding allows for easy storage and retrieval of information for patient care, research, planning, facility management etc.

Coding enables fair reimbursement for health care services and communicates in a predictable, consistent and reproducible manner.

Benefits provided by medical schemes can be appropriately managed with access to sound diagnostic data.

3. Implementation in S A

The Council for Medical Schemes supports the need for industry-wide implementation of ICD-10, as well as the importance of entrenching this standard through legislation.

The Private Health Information Standards Committee (PHISC), a voluntary body representing all stakeholders in the medical industry in SA, recently submitted a document to the National Task Team of the Dept of Health containing, inter alia, recommendations on technical and operational issues for implementation of ICD-10 in the SA environment.

Compulsory from 1 January 2004, the Medical Schemes Act 131 of 1998 introduced a minimum set of benefits which should be

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covered by each benefit option offered by a medical scheme without limitation.

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The objectives of the specification of the prescribed minimum benefits are

1) To avoid incidents where individuals lose their medical scheme cover in the event of serious illness and the consequent risk of unfunded utilisation of public hospitals

2) To encourage improved efficiency in the allocation of private and public health care resources.

The most transparent and scientific way for both the legislator and the health care industry to effectively implement and manage this legislation, would be by way of a comprehensive standardised list of possible ICD-10 codes for the relevant diseases and injuries linked to appropriate treatment protocols.

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4. The basic structure and principles of classification of the ICD

The ICD is a variable-axis classification;

The structure has developed out of that proposed by William Farr in the early days of international discussions on classification structure;

His scheme was that, for all practical, epidemiological purposes, statistical data on diseases should be grouped in the following way:

epidemic diseases

constitutional or general diseases

local diseases arranged by site

developmental diseases

injuries.

This pattern can be identified in the chapters of ICD-10. It has stood the test of time and, though in some ways arbitrary, is still regarded as a more useful structure for general epidemiological purposes than any of the alternatives tested.

In place of the purely numeric coding system of previous revisions (up to the ninth) the Tenth Revision uses an alphanumeric code with a letter in the first position and a number in the second, third and fouth positions.

The forth character is preceded by a decimal point.

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Possible code numbers range from A00.0 to Z99.9.

The letter U is not used.

Codes U00-U49 may be used for the provisional assignment of new diseases of uncertain etiology.

Codes U50-U99 are reserved for research, e.g. when testing an alternative subclassification for a special project.

The descriptions of the ICD must be used as reflected in Volumes I and III and may not be altered or abbreviated.

Abreviations: NEC: Not Elsewhere Classified

NOS: Not Otherwise Specified

The basic ICD is a single coded list of three-character categories, each of which can be further divided into up to ten four-character subcategories, e.g.

J11 Influenza, virus not identified

J11.0 Influenza with pneumonia, virus not identified (Influenzal (broncho) pneumonia, unspecified or specific

virus not identified)

J11.1 Influenza with other respiratory manifestations, virus not

Identified Influenza not otherwise specified (NOS) Influenzal:

acute upper respiratory infection laryngitis pharyngitis pleural effusion

(unspecified or specific virus not identified)

J11.8 Influenza with other manifestations, virus not identified

Encephalopathy due to influenza Influenzal: unspecified or specific

virus not identified gastroenteritis myocarditis (acute)

Note: The four-character subcategories add more specific detail to that diagnosis, identifying, for example, different varieties of the three-character condition.

The following is a further example of a basic ICD; a four-character subcategory;

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as well as a combination of dagger and asterisk code:

E10: Insulin-dependent diabetes mellitus which includes brittle, juvenile-onset, ketosis-prone,Type I;

E10.0: Insulin-dependent diabetes mellitus with coma - the specialist physician who treats the patient in the intensive care unit for diabetes mellitus with coma, will use this code.

E10.5: Insulin-dependent diabetes mellitus with peripheral circulatory complications (which includes diabetic gangrene and ulcer) - the orthopaedic surgeon who codes for amputation procedure in a patient with insulin-dependent diabetes mellitus, will have to use this code;

E10.3†H28.0*: Insulin-dependent diabetes mellitus with ophthalmic complications / Diabetic cataract - the ophthalmologist who codes for removal of cataract resulting from insulin-dependent diabetes mellitus with ophthalmic complications, will have to use this combination of codes

Note: The dagger (†) and asterisk (*) combination of codes will later be

discussed in more detail.

5. Three volumes on ICD-10:

VOLUME ONE contains a listing of all the ICD-10 codes and their associated conditions according to body systems; the classification of morphology of neoplasms; special tabulation lists; definitions; and nomenclature regulations.

It is composed of the list of three-character categories; the tabular list of inclusions; exclusions (listed in other, more appropriate categories) and four-character subdivisions e.g.

J03 Acute tonsillitisExcludes: peritonsillar abscess (J36)

sore throat: NOS (not otherwise specified) (J02.9) acute (J02.-) streptococcal (J02.0)

J03.0Streptococcal tonsillitis

J03.8Acute tonsillitis due to other specified organsisms

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Use additional code (B95-B97), to identify infectious agent.

Excludes: herpesviral [herpes simplex] pharyngotonsillitis (B00.2)

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J03.9Acute tonsillitis, unspecifiedTonsillitis (acute): NOS follicular gangrenous infective ulcerative

Although it is theoretically possible for a coder to arrive at the correct code by the use of volume I alone, this would be time-consuming and could lead to errors in assignment.

VOLUME THREE is the Alphabetical Index as a guide to the classification (contained in Volume 1) and has three main sections:

Section One

- an alphabetical index to diseases and nature of injury

Section Two

- the index of external causes of injury. These are not diagnoses but descriptions of the circumstances in which the violence occurred e.g. fire, assault, collision

Section Three - the index of drugs and other substances

The introduction gives instructions on how to use it. These instructions should be read carefully before starting to code.

The introduction to the Index of volume 3 also provides important information about its relationship with Volume 1.

VOLUME TWO provides guidance to users of the ICD;

6. Three-character categories

Within each block of homogenous three-character categories, some of the three-character categories are for single conditions (without four-character subcategories), selected because of their frequency, severity or susceptibility to public health intervention e.g.

A09: Diarrhoea and gastroenteritis of presumed infectious origin within the block for Intestinal infectious diseases (A00-A09)

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A38: Scarlet fever within the block for other bacterial diseases (A30-A49)

G20: Parkinson’s disease within the block for extrapyramidal and movement disorders

I64: Stroke, not specified as haemorrhage or infarction within the block for cerebrovascular diseases

K20: Oesophagitis within the block for diseases of oesophagus, stomach and duodenum.

7. Supplementary subdivisions for use at the fifth or subsequent character level

The fifth and subsequent character levels are usually subclassifications along a different axis from the forth character. They are found in:

CHAPTER XIII – subdivisions by anatomical site e.g. in diseases of the musculoskeletal system and connective tissue:

Example:

M11.1 Familial chondrocalcinosisM11.10 Familial chondrocalcinosis – multiple sitesM11.11 Familial chondrocalcinosis – shoulder regionM11.12 Familial chondrocalcinosis – upper arm (elbow joint)M11.16 Familial chondrocalcinosis – lower leg (knee joint)

CHAPTER XIX – subdivisions to indicate open and closed fractures as wel as intracranial, intrathoracic and intra-abdominal injuries with and without open wound:

Examples:

S06.2 Diffuse brain injuryS06.20 Diffuse brain injury without open intracranial woundS06.21 Diffuse brain injury with open intracranial wound

S52.0 Fracture of upper end of ulnaS52.00 Fracture of upper end of ulna – closedS52.22 Fracture of upper end of ulna – open

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CHAPTER XX – External causes of morbidity and mortality - subdivisions to indicate the type of activity being undertaken at the time of the event:

Example:

V03 Pedestrian injured in collision with car, pick-up truck or van

V03.0 Pedestrian injured in collision with car, pick-up truck or van – Nontraffic accidentV03.1 Pedestrian injured in collision with car, pick-up truck or van – Traffic accident

8. Combination Codes

a) Dagger and Asterisk Codes

The coder would sometimes need to use two codes in order to fully identify one condition, as occurs with the Dagger and Asterisk Codes.

The underlying disease (dagger code) is linked to the signs and symptoms (asterisk code) that the patient is presenting with.

The dagger code should always be quoted first.

b) Three specific rules regarding the combined dagger and asterisk codes:

i. If the dagger and asterisk symbols both appear in the rubric heading, all terms classifiable to that rubric are subject to dual classification and all have the same alternative (asterisk) code e.g. in category A17.0: Tuberculous meningitis (G01*)

Tuberculosis of meningitis (cerebral) (spinal)

ii. If the dagger symbol appears in the rubric heading, but the asterisk does not, the codes listed within that rubric are subject to dual classification but they have different alternative asterisk codes e.g. the codes in category A18.0: Tuberculosis of bones and joints

iii. If neither the dagger nor the asterisk appears in the title, the rubric as a whole is not subject to dual classification, but certain sub-headings may be e.g. as in category A54 hosting, amongst others, A54.4†: Gonococcal infection of musculoskeletal system

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It is a principle of the ICD that the dagger code is the primary code and must always be used.

Asterisk codes appear as three-character categories as shown below.

There are separate categories for the same conditions occurring when a particular disease is not specified as the underlying cause. For example, catagories G20 and G21 are for forms of Parkinsonism that are not manifestations of other diseases assigned elsewhere, while category G22* is for “Parkinsonsim in diseases classified elsewhere”.

Corresponding dagger codes are given for conditions mentioned in asterisk categories e.g. for Syphilitic parkinsonism in G22*, the dagger code is A52.1† (Symptomatic neurosyphilis).

The following asterisk categories should never be used alone; they must always be used in addition to a dagger code:

D63*

D77*

E35* E90* F00* F02* G01* G59*

G02* G63*

G05* G73*

G07* G94*

G13* G99*

G22*

G26*

G32*

G46*

G53*

G55*

H03* H58*

H06* H62*

H13* H67*

H19* H75*

H22* H82*

H28* H94*

H32*

H36*

H42*

H45*

H48*

I32* I39* I41* I43* I52* I68* I79* I98* J17* J91* J99* K23*

K67*

K77*

K87*

K93*

L14* L45* L54* L62* L86* L99* M01* M73*

M03* M82*

M07* M90*

M09*

M14*

M36*

M49*

M63*

M68*

N08 N16 N22 N29 N33 N37 N51 N74 N77

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* * * * * * * * * P75*

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9. The following categories apply only to females:

A34B37.3C51-C58 C79.6D06.0-D06.9

D07.0-D07.3

D25-D28

D39.0-D39.9

E28.0-E28.9 E89.4F52.5 F53.0-F53.9I86.3L29.2 L70.5M80.0-M80.1

M81.0-M81.1

M83.0

N70-N98 N99.2-N99.3

O00-O99P54.6Q50-Q52R87S31.4 S37.4-S37.6T19.2-T19.3 T83.3Y76.-Z01.4Z32-Z36

Z12.4Z39.0-Z39.2

Z30.1Z43.7

Z30.3Z87.5

Z30.5 Z97.5

Z31.1 Z31.2

10. The following catetories apply only to males:

B26.0C60-C63D07.4-D07.6

D17.6 D29.0-D29.9

D40.0-D40.9

E29.0-E29.9 E89.5F52.4I86.1L29.1N40-N51Q53-Q55R86S31.2-S31.3Z12.5

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11. Morbidity coding

Main Condition - Principal Diagnosis

The condition to be used for single-condition morbidity analysis is the main condition treated or investigated during the relevant episode of health care.

The main condition is defined as the condition, diagnosed at the end of the episode of health care, primarily responsible for the patient’s need for treatment or investigation.

If there is more than one such condition, the one held most responsible for the greatest use of resources should be selected (Principal Diagnosis).

Furthermore, the Principal Diagnosis is typically the clinical condition that is ultimately determined to have caused a patient’s admission to hospital.

It is the Principal Diagnosis that is established after investigation and diagnostic tests.

The Principal Diagnosis is the discharge diagnosis.

The Principal Diagnosis may differ from the admitting diagnosis (as was indicated in Item 1, p 1).

A complication may become the Principal Diagnosis e.g post-operative:

T81.0 Haemorrhage and haematoma complicating a

procedure, not elsewhere classified.

In addition to the Principal Condition, the record should, whenever possible, also list separately other conditions or problems dealt with during the episode of health care.

Other conditions are defined as those that coexist or develop during the episode of health care and affect the management of the patient.

Conditions related to an earlier episode that have no bearing on the current episode should not be recorded.

If no definite diagnosis has been established by the end of an episode of health care, then the information that permits the

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greatest degree of specificity and knowledge about the condition that necessitated care or investigation should be recorded.

Coding of conditions to which the dagger and asterisk system applies

If applicable, both dagger and asterisk codes should be used for the main condition, since they denote two different pathways for a single condition.

Example: Principal condition: Measles pneumonia

Other conditions:

B05.2† J17.1* Measles complicated by pneumonia/Pneumonia in viral diseases classified elsewhere

Coding of suspected conditions, symptoms and abnormal findings and

non-illness situations (Chapters XVIII and XXI)

If the period of health care was for a hospitalised patient, the coder should be cautious about classifying the Principal Condition to Chapters XVIII and XXI.

If a more specific diagnosis has not been made at the end of the inpatient stay, or if there was truly no codable current illness or injury, then codes from the above chapters are permissible.

These categories can however be used in the normal way for other episodes of contact with health services.

If, after an episode of health care, the main condition is still recorded as “suspected”, “questionable”’ etc., and there is no further information or clarification, the suspected diagnosis must be coded as if established e.g.

Example: Main condition: Suspected acute cholecystitis

Other condition:

K81.1 Acute cholecystitis (main condition)

Coding of multiple conditions

Where multiple conditions are recorded in a category entitled “Multiple …”, and no single condition dominates, the code for the “Multiple …” category should be used as the preferred code.

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Optional additional codes may be added for individual conditions listed.

Such coding applies mainly to conditions associated with HIV disease; injuries and sequelae.

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Examples:

B21.7 HIV resulting in multiple malignantneoplasms

T04.0 Crushing injuries involving head with neck

T04.8 Crushing injuries of thorax with abdomen,

lower back and pelvis with limb(s)

Coding of combination categories

The ICD provides certain categories where two conditions or a condition and an associated secondary process can be represented by a single code.

Such combination categories should be used as the main condition where appropriate information is recorded.

The Alphabetical Index indicates where such combinations are provided for, under the indent “with”, which appears immediately after the lead term.

Example: Hyperthyroidism (latent) (pre-adult) (recurrent)

E05.9)(hyperthyroidism) With goiter (diffuse)

E05.0

Coding of external causes of morbidity

For injuries and other conditions due to external causes, both the nature of the condition and the circumstances of the external cause should be coded.

The preferred “principal condition” code should be that describing the nature of the condition.

This will usually, but not always, be classifiable to Chapter XIX: Injury, poisoning and certain other consequences of external causes.

The appropriate code from Chapter XX (indicating the external cause) would be used as an additional code.

Example:

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S72.00 Closed fracture of neck of femur (Principal

condition)

S50.0 Contusion of elbow (further injury sustained,

as secondary diagnosis)

W01.4 Fall on same level from slipping, tripping and

stumbling on street or highway (external cause)

Coding of sequelae (late effects) of certain conditions

The ICD provides a number of categories entitled “Sequelae of…”which may be used to indicate conditions no longer present as the cause of the current problem undergoing treatment or investigation.

Sequelae categories for sequelae conditions that are no longer in active phase:

B90-B94, E64.-, E68, G09, I69.-, O97, T90-T98, Y85-Y89

Example:

Osteoarthritis of hip joint due to old hip fracture from motor vehicle accident 10 years ago

M16.5 Post-traumatic coxarthrosis (Principalcondition)

T93.1 Sequelae of fracture of femur (Additional code)

Y85.0 Sequelae of motor vehicle accident (Additional

code)

Coding of acute and chronic conditions

Where the main condition is recorded as being both acute (or subacute) and chronic, and the ICD provides separate categories or subcategories for each, but not for the combination, the category for the acute condition should be used as the preferred main condition

Example:

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Main condition: Acute and chronic cholecystitisOther conditions:

K81.0 Acute cholecystitis Note: The code for chronic cholecystitis (K81.1) may be used as an additional

code

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Coding of postprocedural conditions and complications

Categories are provided in Chapter XIX (T80-T88) for certain complications related to surgical and other procedures, e.g. surgical wound infections, mechanical complications of implanted devices, shock, etc.

Most body-system chapters also contain categories for conditions that occur either as a consequence of specific procedures and techniques or as a result of the removal of an organ, e.g. postmastectomy lymphoedema syndrome, postirradiation hypothyroidism.

Some conditions e.g. pneumonia, pulmonary embolism, that may arise in the postprocedural period are not considered unique entities and are, therefore, coded in the usual way.

An optional additional code from Y83-Y84: (Surgical and medical procedures as the cause of abnormal reaction of the patient, or of later complication, without mention of misadventure at the time of the procedure), may be added to identify the relationship to a procedure.

Example:

Main condition: Hypothyroidism since thyroidectomy 1 year agoOther conditions:

E89.0 Hypothyroidism (Main Condition)

Categories for Postprocedural Disorders:E89.- Postprocedural endocrine and metabolic disorders, not elsewhere classifiedG97.- Postprocedural disorders of nervous system, not elsewhere classifiedH59.- Postprocedural disorders of eye and adnexa, not elsewhere classifiedH95.- Postprocedural disorders of ear and mastoid process, not elsewhere classifiedI97.- Postprocedural disorders of circulatory system, not elsewhere classifiedJ95.- Postprocedural respiratory disorders, not elsewhere classifiedK91.- Postprocedural disorders of digestive system, not elsewhere classifiedM96.- Postprocedural musculoskeletal disorders, not elsewhere classifiedN99.- Postprocedural disorders of genitourinary system, not elsewhere classified

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12. Coding in ICD-10 by a practical method

In the USA the following basic guidelines are used for diagnostic coding:

The primary diagnosis which is the code reflecting the current, most significant reason for the current services or procedures provided should be used;

Diseases and conditions that coexist during an encounter and effect the management of the patient’s care should be sequenced after the primary diagnosis;

Signs and symptoms are coded when there is no other definitive diagnosis or cause listed for the condition e.g. nausea & vomiting;

If two or more diagnoses of equal importance are listed, the principal diagnosis becomes the one for which definitive treatment was provided, either surgical or non-surgical;

Unspecified ICD codes and general terms may not clarify the medical necessity issue; therefore the coder should be as specific as possible in describing the patient’s condition, illness or disease;

Unspecified ICD codes are reported when the diagnosis has not been finalised;

To report multiple injuries, list the conditions treated by the doctor in order of importance, with the major problem first;

For multiple diseases, code only the disease and conditions that have an impact on the management of the patient. List the major management problem first.

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References:International Statistical Classification of Diseases and Related Health Problems (ICD-10) (Tenth Rivision) Volumes 1, 2 and 3Extracts from minutes of various meetings of PHISC and its sub-committeesExtracts from the minutes of a meeting of the ICD-10 Task Team held on 2004-02-18‘Code it Right’ as published by Medicode 2000

ICD-10 codes used by permission of WHO, from: International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10). Vols 1-3. Geneva, World Health Organization, 1992.

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