For internal use only, by 5th year medical
students of the Dept of Family Medicine of
the University of Pretoria - 2004
ICD-10
International 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). Vols
1-3. Geneva, World Health Organization, 1992.
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

The purpose of ICD is to establish a systematic recording, analysis,

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
to which morbid entities are assigned according to established
criteria.
interpretation and comparison of morbidity and mortality data
collected in different countries or areas and at different times.
 “diagnosis” e.g. C16.1: Malignant neoplasm of fundus of
stomach;
 “reason for admission” e.g. R10.0: Acute abdomen severe and generalised abdominal pain with abdominal
rigidity;
2
 “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 covered by each
benefit option offered by a medical scheme without limitation.
3

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.
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.

Possible code numbers range from A00.0 to Z99.9.
4

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;
as well as a combination of dagger and asterisk code:
 E10: Insulin-dependent diabetes mellitus which includes
brittle, juvenile-onset, ketosis-prone,Type I;
5
 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 tonsillitis
Excludes:
peritonsillar abscess (J36)
sore throat:
 NOS (not otherwise specified) (J02.9)
 acute (J02.-)
 streptococcal (J02.0)
J03.0 Streptococcal tonsillitis
J03.8 Acute tonsillitis due to other specified organsisms
Use additional code (B95-B97), to identify infectious agent.
Excludes:
herpesviral [herpes simplex] pharyngotonsillitis
(B00.2)
6
J03.9 Acute tonsillitis, unspecified
Tonsillitis (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)
7
 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
M11.10
M11.11
M11.12
M11.16
Familial chondrocalcinosis
Familial chondrocalcinosis –
Familial chondrocalcinosis –
Familial chondrocalcinosis –
Familial chondrocalcinosis –
multiple sites
shoulder region
upper arm (elbow joint)
lower leg (knee joint)
 CHAPTER XIX – subdivisions to indicate open and closed
fractures as wel as intracranial, intrathoracic and intraabdominal injuries with and without open wound:
Examples:
 S06.2 Diffuse brain injury
S06.20 Diffuse brain injury without open intracranial wound
S06.21 Diffuse brain injury with open intracranial wound
 S52.0 Fracture of upper end of ulna
S52.00 Fracture of upper end of ulna – closed
S52.22 Fracture of upper end of ulna – open
8
 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 accident
V03.1 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
 It is a principle of the ICD that the dagger code is the primary code
and must always be used.
9
 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*
P75*
10
9. The following categories apply only to females:
A34
B37.3
C51-C58
C79.6
D06.0-D06.9
D07.0-D07.3
E28.0-E28.9
E89.4
F52.5
F53.0-F53.9
D25-D28
D39.0-D39.9
I86.3
L29.2
L70.5
M80.0-M80.1
M81.0-M81.1
N70-N98
N99.2-N99.3
M83.0
O00-O99
P54.6
Q50-Q52
R87
S31.4
S37.4-S37.6
T19.2-T19.3
T83.3
Y76.Z01.4
Z32-Z36
Z12.4
Z39.0-Z39.2
Z30.1
Z43.7
Z30.3
Z87.5
Z30.5
Z97.5
Z31.1
Z31.2
10. The following catetories apply only to males:
B26.0
C60-C63
D07.4-D07.6
D17.6
E29.0-E29.9
E89.5
D29.0-D29.9
D40.0-D40.9
F52.4
I86.1
L29.1
N40-N51
Q53-Q55
R86
S31.2-S31.3
Z12.5
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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

A complication may become the Principal Diagnosis e.g postoperative:
was indicated in Item 1, p 1).
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 greatest degree of
specificity and knowledge about the condition that necessitated care or
investigation should be recorded.
12
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:
B05.2† J17.1*
Principal condition:
Other conditions:
Measles pneumonia
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:
Other condition:
Suspected acute cholecystitis
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.

Optional additional codes may be added for individual conditions listed.

Such coding applies mainly to conditions associated with HIV disease;
injuries and sequelae.
13
Examples:
B21.7
HIV resulting in multiple malignant
neoplasms
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:
S72.00
Closed fracture of neck of femur (Principal
condition)
S50.0
Contusion of elbow (further injury sustained,
as secondary diagnosis)
14
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 (Principal
condition)
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:
Main condition:
Other conditions:
Acute and chronic cholecystitis
K81.0
Acute cholecystitis
Note: The code for chronic cholecystitis (K81.1) may be used as an additional
code
15
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:
Other conditions:
E89.0
Hypothyroidism since thyroidectomy 1 year ago
Hypothyroidism (Main Condition)
Categories for Postprocedural Disorders:
E89.G97.H59.H95.I97.J95.K91.M96.N99.-
Postprocedural
Postprocedural
Postprocedural
Postprocedural
Postprocedural
Postprocedural
Postprocedural
Postprocedural
Postprocedural
endocrine and metabolic disorders, not elsewhere classified
disorders of nervous system, not elsewhere classified
disorders of eye and adnexa, not elsewhere classified
disorders of ear and mastoid process, not elsewhere classified
disorders of circulatory system, not elsewhere classified
respiratory disorders, not elsewhere classified
disorders of digestive system, not elsewhere classified
musculoskeletal disorders, not elsewhere classified
disorders of genitourinary system, not elsewhere classified
16
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.
17
References:
International Statistical Classification of Diseases and Related Health Problems (ICD-10)
(Tenth Rivision) Volumes 1, 2 and 3
Extracts from minutes of various meetings of PHISC and its sub-committees
Extracts 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.
18