Scientific Data Documentation
International Classification Of Diseases - 9 - CM, (1979)
*SEE ICD-9-CM DATASET NAMES
ABSTRACT
Purpose of The ICD-9-CM File
The International Classification of Diseases, 9th Revision,
Clinical Modification (ICD-9-CM) is based on the official
version of the World Health Organization's 9th Revision,
International Classification of Diseases (ICD-9). ICD-9
is designed for the classification of morbidity and
mortality information for statistical purposes, and for the
indexing of hospital records by disease and operations, for
data storage and retrieval.
This modification of ICD-9 supplants the Eighth Revision
International Classification of Diseases, Adapted for Use
in the United States (ICDA-8) and the Hospital Adaptation
of ICDA (H-ICDA).
Description of The ICD-9-CM File
This third edition of the International Classification of
Diseases, 9th Revision, Clinical Modification (ICD-9-CM) is
being published by the United States Government in
recognition of its responsibility to promulgate this
classification throughout the United States for mobidity
coding. The International Classification of Diseases, 9th
Revision, PUBLISHED BY THE World Health Organization (WHO)
is the foundation of the ICD-9-CM and continues to be the
classification employed in cause-of-death coding in the
United States. The ICD-9-CM is completely comparable with
the ICD-9. The WHO Collaborating Center for Classification
of Diseases in North America serves as liaison between the
international obligations for comparable classifications
and the national health data needs of the United States.
The ICD-9-CM is recommended for use in all clinical
settings but is required for reporting diagnoses and
diseases to all U.S. Public Health Service and Health Care
Financing Administration programs.
ICD-9-CM extensions, interpretations, modifications,
addenda, or errata other than those approved by the U.S.
Public Health Service and the Health Care Financing
Administration are not to be considered official and should
not be utilized. Continuous maintenance of the ICD-9-CM is
the responsibility of the Federal Government. However,
because the ICD-9-CM represents the best in contemporary
thinking of clinicians, nosologists, epidemiologists, and
statisticians from both public and private sectors, no
future modifications will be considered without extensive
advice from the appropriate representatives of all major
users.
All official authorized addenda through October 1, 1988,
have been included in this third edition.
BACKGROUND
Introduction
In February 1977, a Steering Committee was convened by the
National Center for Health Statistics to provide advice and
counsel to the development of a clinical modification of
the ICD-9. The organizations represented on the Steering
Committee included:
American Association of Health Data Systems
American Hospital Association
American Medical Record Association
Association for Health Records
Council on Clinical Classifications
Health Care Financing Administration,
Department of Health and Human Services
WHO Center for Classification of Diseases for North
America, sponsored by the National Center for Health
Statistics, Department of Health and Human Services
The Council on Clinical Classifications is sponsored by:
American Academy of Pediatrics
American College of Obstetricians and Gynecologists
American College of Physicians
American College of Surgeons
American Psychiatric Association
Commission on Professional and Hospital Activities
The Steering Committee met periodically in 1977. Clinical
guidance and technical input were provided by Task Forces
on Classification from the Council on Clinical
Classification's sponsoring organizations.
ICD-9-CM is a clinical modification of the World Health
Organization's International Classification of Diseases,
9th Revision (ICD-9). The term "clinical" is used to
emphasize the modification's intent: to serve as a useful
tool in the area of classification of morbidity data for
indexing of medical records, medical care review, and
ambulatory and other medical care programs, as well as for
basic health statistics. To describe the clinical picture
of the patient, the codes must be more precise than those
needed only for statistical groupings and trend analysis.
Development
The concept of extending the International Classification
of Diseases for use in hospital indexing was originally
developed in response to a need for a more efficient basis
for storage and retrieval of diagnostic data. In 1950, the
U.S. Public Health Service and the Veterans Administration
began independent tests of the International Classification
of Diseases for hospital indexing purposes. In the
following year, the Columbia Presbyterian Medical Center in
New York City adopted the International Classification of
Diseases, 6th Revision, with some modifications for use in
its medical record department. A few years later, the
Commission on Professional and Hospital Activities adopted
the International Classification of Diseases with similar
modifications for use in hospitals participating in the
Professional Activity Study.
The problem of adapting ICD for indexing hospital records
was taken up by the U.S. National Committee on Vital and
Health Statistics through its subcomittee on hospital
statistics. The subcommittee reviewed the modifications
made by the various users of ICD and proposed that uniform
changes be made. This was done by a small working party.
In view of the growing interest in the use of the
International Classification of Diseases for hospital
indexing, a study was undertaken in 1956 by the American
Hospital Association and the American Medical Record
Association (then the American Association of Medical
Record Librarians) of the relative efficiencies of coding
systems for diagnostic indexing. This study indicated that
the International Classification of Diseases provided a
suitable and efficient framework for indexing hospital
records. The major users of the International
Classification of Diseases for hospital indexing purposes
then consolidated their experiences and an adaptation was
first published in December 1959. A revision was issued in
1962 and the first "Classification of Operations and
Treatments" was included.
In 1966, the international conference for the revision of
the International Classification of Diseases noted that
the 8th revision of ICD has been constructed with hospital
indexing in mind and considered that the revised
classification would be suitable, in itself, for hospital
use in some countries. However, it was recognized that
the basic classification might provide inadequate detail
for diagnostic indexing in other countries. A group of
consultants was asked to study the 8th revision of ICD (ICD
8) for applicability to various users in the United States.
This group recommended that further detail be provided for
coding of hospital and morbidity data. The American
hospital Association was requested to develop the needed
adaptation proposals. This was done by an advisory
committee (the Advisory Committee to the Central Office on
ICDA). In 1968 the United States Public Health Service
published the product, Eighth Revision International
Classification of Diseases, Adapted for Use in the United
States (PHS publication 1693). This became commonly known
as ICDA-8, and beginning in 1968 it served as the basis for
coding diagnostic data for both official morbidity
statistics in the United States.
In 1968, the Commission on Professional and Hospital
Activities (CPHA) of Ann Arbor, Michigan, published the
Hospital Adaptation of ICDA (H-ICDA) based on both the
original ICD-8 and ICDA-8. In 1973, CPHA published a
revision of H-ICDA, referred to as H-ICDA-2. Hospitals
throughout the United States have been divided in their
usage of these classifications. Effective January 1979,
ICD-9-CM provides a single classification intended
primarily for use in the United States replacing these
earlier related but somewhat dissimilar classifications.
CHARACTERISTICS OF ICD-9-CM
General Information
ICD-9-CM is published as a three-volume set:
Volume 1 Diseases: Tabular List
Volume 2 Diseases: Alphabetic Index
Volume 3 Procedures: Tabular List and Alphabetic
Index
ICD-9-CM far exceeds its predecessors in the number of
codes provided. The disease classification has been
expanded to include health-related conditions and to
provide greater specificity at the fifth-digit level of
detail. These fifth digits are not optional; they are
intended for use in recording the information substantiated
in the clinical record.
Volume 1 of ICD-9-CM contains five appendices:
Appendix A Morphology of Neoplasms
Appendix B Glossary of Mental Disorders
Appendix C Classification of Drugs by American
Hospital Formulary Service List Number and Their ICD-9-CM
Equivalents
Appendix D Classification of Industrial Accidents
According to Agency
Appendix E List of Three-Digit Categories
These appendices are included as a reference to the user in
order to provide further information about the patient's
clinical picture, to further define a diagnostic statement,
to aid in classifying new drugs, or to reference three-
digit categories.
Volume 2 of the ICD-9-CM contains many diagnostic terms
which do not appear in Volume 1 since the index includes
most diagnostic terms currently in use.
Volume 3 of ICD-9-CM also contains increased clinical
detail over its predecessors, and this is accommodated by
expansion of the rubrics from three to four digits.
The Disease Classification
General Information
ICD-9-CM is totally compatible with its parent system, ICD-
9, thus meeting the need for comparability of morbidity and
mortality statistics at the international level. A few
fourth-digit codes were created in existing three-digit
rubrics only when the necessary detail could not be
accommodated by the use of a fifth-digit sub-
classification. In these few instances (28 three-digit
categories) the special symbol > > to the left of the code
indicates that the content of that category differs from
its ICD-9 counterpart, but even in such cases it is
possible to recreate the original ICD-9 rubrics through
appropriate recombination of the ICD-9-CM categories. To
ensure that each rubric of ICD-9-CM collapses back to its
ICD-9 counterpart, several specifications governed the ICD-
9-CM disease classification.
Specifications for The Tabular List
1. Three-digit rubrics and their contents are unchanged
from ICD-9.
2. The sequence of three-digit rubrics is unchanged from
ICD-9.
3. Three-digit rubrics are not added to the main body of
the classification.
4. Unsubdivided three-digit rubrics are subdivided where
necessary to:
a) Add clinical detail
b) Isolate terms for clinical accuracy
5. The modification in ICD-9-CM is accomplished by the
addition of a fifth digit to existing ICD-9 rubrics, except
as noted under #7 below.
6. Four-digit rubrics are added to subdivided three digit
codes only when there is no other means of achieving
desired detail. These codes, unique to ICD-9-CM (twenty-
eight three-digit categories), are marked with the symbol >
> in the Tabular List.
7. The optional dual classification in ICD-9 is modified.
a) Duplicate rubrics are deleted:
1) Four-digit manifestation categories
duplicating etiology entries.
2) Manifestation inclusion terms
duplicating etiology entries.
b) Manifestations of diseases are identified, to the
extent possible, by creating five-digit codes in the
etiology rubrics.
c) When the manifestation of a disease cannot be
included in the etiology rubrics, provision for its
identification is made by retaining the ICD-9 rubrics used
for classifying manifestations of disease.
8. The format of ICD-9-CM is revised from that used in
ICD-9.
a) American spelling of medical terms is used.
b) Inclusion terms are indented beneath the titles
of codes.
c) Codes not to be used for primary tabulation of
disease are printed in italics with the notation, "code
also underlying disease."
1. Format of the Alphabetic Index follows the format of
ICD-9.
2. Main terms in the Alphabetic Index are printed in bold
type face.
3. When two codes are required to indicate etiology and
manifestation, the optional manifestation code appears in
brackets, e.g., diabetic cataract 250.5 +366.41+.
The Procedure Classification
General Information
An important new development occurred with the publication
of ICD-9; a Classification of Procedures in Medicine.
Heretofore, procedure classifications had not been a part
of ICD, but were published with the adaptations to it
produced in the United States.
The ICD-9 Classification of Procedures in Medicine is
published separately from the disease classification in a
series of supplementary documents called fascicles. Each
fascicle contains a classification of modes of therapy,
surgery, radiology, laboratory, and other diagnostic
procedures. The decision to publish each fascicle as a
unique document was made in order to permit its revision on
a separate schedule from the disease classification.
Primary input to Fascicle V, "Surgical Procedures," came
from the United States whose adaptations of ICD had
contained a procedure classification since 1962. This
experience was invaluable in constructing a classifica-
tion to permit analysis of health care services in
hospitals and primary care settings.
The ICD-9-CM Procedure Classification is a modification of
WHO's Fascicle V, "Surgical Procedures," and is published
as Volume 3 of ICD-9-CM. It contains both a Tabular List
and an Alphabetic Index. Greater detail has been added to
the ICD-9-CM Procedure Classification necessitating
expansion of the codes from three to four digits.
Approximately 90% of the rubrics refer to surgical proce-
dures with the remaining 10% accounting for other
investigative and therapeutic procedures.
Specifications for The Procedure Classification
1. The ICD-9-CM Procedure Classification is published in
its own volume containing both a Tabular List and an
Alphabetic Index.
2. The classification is a modification of Fascicle V
"Surgical Procedures" of the ICD-9 Classification of
Procedures in Medicine, working from the draft dated
Geneva, 30 September - 6 October 1975, and labeled WHO/ICD-
9/Rev. Conf. 75.4.
3. All three-digit rubrics in the range 01-86 are
maintained as they appear in Fascicle V, whenever feasible.
4. Nonsurgical procedures are segregated from the surgical
procedures and confined to the rubrics 87-99, whenever
feasible.
5. Selected detail contained in the remaining fascicles of
the ICD-9 Classification of Procedures in medicine is
accommodated where possible.
6. The structure of the classification is based on anatomy
rather than surgical specialty.
7. The ICD-9-CM Procedure Classification is numeric only,
i.e., no alphabetic characters are used.
8. The classification is based on a two-digit structure
with two decimal digits where necessary.
9. Compatibility with the ICD-9 Classification of
Procedures in Medicine was not maintained when a different
axis was deemed more clinically appropriate.
