Instruction Manual

Part 2b

Instructions for Classifying the Multiple Causes of Death, 2021

U.S. Department of Health and Human Services

Centers for Disease Control and Prevention

National Center for Health Statistics

SECTION I – INSTRUCTIONS FOR CLASSIFYING MULTIPLE CAUSES OF DEATH, 2021

SECTION I – INTRODUCTION

A. Introduction

This manual provides instructions to mortality medical coders and nosologists for coding multiple causes of death from death certificates filed in the states. These mortality coding instructions are used by both the State vital statistics programs and the National Center for Health Statistics (NCHS), which is the Federal agency responsible for the compilation of U.S. statistics on causes of death. NCHS is part of the Centers for Disease Control and Prevention.

In coding causes of death, NCHS adheres to the World Health Organization Nomenclature Regulations specified in the most recent revision of the International Statistical Classification of Diseases and Related Health Problems (ICD). NCHS also uses the ICD international rules for selecting the underlying cause of death for primary mortality tabulation in accordance with the international rules.

Beginning with deaths occurring in 1999, the Tenth Revision of the ICD (ICD-10) is being used for coding and classifying causes of death. This revision of the Classification is published by the World Health Organization (WHO) and consists of three volumes.

Volume 1 contains a list of three-character categories, the tabular list of inclusions, and the four-character subcategories. The supplementary Z code appears in Volume 1 but is not used for classifying mortality data. Optional fifth characters are provided for certain categories and an optional independent four-character coding system is provided to classify histological varieties of neoplasm, prefixed by the letter M (for morphology) and followed by a fifth character indicating behavior. These optional codes, except those for place of occurrence of external cause and activity code related to external cause codes, are not used in NCHS. The place code and activity code are used as supplementary codes rather than as additional characters. Volume 2 includes the international rules and notes for use in classifying and tabulating underlying cause-of-death data. Volume 3 is an alphabetical index containing a comprehensive list of terms for use in coding. Copies of these volumes may be purchased in hard-copy or on diskette from the following address:

WHO Publications Center
49 Sheridan Avenue
Albany, New York 12210
Tel. 518-436-9686

NCHS has prepared an updated version of Volume 1 and Volume 3 to be used for both underlying and multiple cause-of-death coding. The major purpose of the updated version is to provide a single published source of code assignments including terms not indexed in Volume 3 of ICD-10. NCHS has included all nonindexed terms encountered in the coding of deaths during 1979-1994, under the Ninth Revision of the International Classification of Diseases (ICD-9). With the availability of the updated Volumes 1 and 3, NCHS will discontinue publishing the Part 2e manual, Nonindexed Terms, Standard Abbreviations, and State Geographic Codes Used in Mortality Data Classification, which was first published in 1983. Due to copyright considerations, the updated Volumes 1 and 3 may not be reproduced for distribution outside of NCHS and State vital statistics agencies.

The basic purpose of this manual is to document concepts and instructions for coding multiple causes of death, which were developed by NCHS for use with the Eighth Revision of the ICD adapted for use in the United States (ICDA-8), and which were updated to ICD-9, and subsequently to ICD-10. The coding concepts are generally consistent with provisions of ICD-10. Thus, this manual should be used with ICD-10, Volumes 1 and 3 as updated by NCHS. The list of abbreviations used in medical terminology (Appendix A), the list of synonymous sites (Appendix B), and the list of geographic codes (Appendix C) are included in this publication.

NCHS does not use the “dagger and asterisk” system which WHO introduced in ICD-9 and continued in ICD-10. For some medical conditions, this system provides two codes, which distinguish between the etiology or underlying disease process and the manifestation or complication for selected conditions. The etiology or underlying disease codes is denoted with a dagger (†) and the manifestation or complication code by an asterisk (*) following the code. For example, Coxsackie myocarditis has a code (B33.2†) marked with a dagger in the chapter for infectious and parasitic diseases and a different code (I41.1*) marked with an asterisk in the chapter for diseases of the circulatory system. Similarly, diabetic nephropathy has a dagger code (E14.2 †) in the chapter relating to endocrine disease and an asterisk code (N08.3*) in the genitourinary system chapter. Under ICD-9, limited use was made of the asterisk codes in classifying mortality data for data years 1979-1982. Effective July 1982 the use of asterisk codes in mortality coding was discontinued and will not be used in the 10^th revision for mortality coding. NCHS assigns only the dagger code to such conditions.

The multiple cause-of-death codes are used as inputs to the ACME program (Automated Classification of Medical Entities) developed by NCHS to automatically select the underlying cause of death, and the TRANSAX program (Translation of Axes) used to produce multiple cause-of-death statistics, beginning with deaths occurring in 1968. As inputs, the computer programs require codes for each condition reported on the death certificate, usually in the order in which the information is recorded.

The outputs of the ACME program are the traditional underlying cause-of-death codes selected according to the selection and modification rules of the Classification, the same cause that would be selected using manual underlying cause-of-death coding instructions specified in Instruction Manual Part 2a. Thus, a single cause is associated with each decedent.

Using the same input codes, the TRANSAX program generates two sets of outputs: “entity-axis” codes that reflect the placement of each condition on the certificate for each decedent; and “record-axis” codes that, where appropriate, link two or more diagnostic conditions to form composite codes that are classifiable to a single code, according to the provisions of the Classification. Record axis codes are preferred for multiple cause tabulation to better convey the intent of the certifier, and to eliminate redundant cause-of-death information (see Instruction Manual Part 2f).

Major revisions from previous manuals

1. Corrections have been made to clarify instructions, spelling, and format throughout the manual. These changes are not specifically noted.
2.       Section V, Part J, 5, Additional Examples, edited first example and added new example to demonstrate parked car.
3. Appendix G, added new code info for Vaping related disorder.
4. Appendix G, added new term “Sudden Acute Respiratory Syndrome Coronavirus Type 2” to COVID-19 indexing list.
5. Appendix H, #28, edited Toxicity code to reflect indexing.
6. Appendix H, added new drug example.

Other manuals relating to coding causes of death are:

Part 2a, NCHS Instructions for Classifying the Underlying Cause of Death, 2021

Part 2c, ICD-10 ACME Decision Tables for Classifying the Underlying Causes of Death, 2021

Part 2k, Instructions for the Automated Classification of the Initiating and Multiple Causes of Fetal Death, 2021

Part 2s, SuperMICAR Data Entry Instruction, 2011

B. Medical Certification

The U. S. Standard Certificate of Death provides spaces for the certifying physician, coroner, or medical examiner to record pertinent information concerning the diseases, morbid conditions, and injuries which either resulted in or contributed to death as well as the circumstances of the accident or violence which produced any such injuries. The medical certification portion of the death certificate includes items 32-44. It is designed to obtain the opinion of the certifier as to the relationship and relative significance of the causes, which he reports.

A cause of death is the morbid condition or disease process, abnormality, injury, or poisoning leading directly or indirectly to death. The underlying cause of death is the disease or injury, which initiated the train of morbid events leading directly or indirectly to death or the circumstances of the accident or violence, which produced the fatal injury. A death often results from the combined effect of two or more conditions. These conditions may be completely unrelated, arising independently of each other or they may be causally related to each other; that is, one cause may lead to another which in turn leads to a third cause, etc.

The order in which the certifier is requested to arrange the causes of death upon the certification form facilitates the selection of the underlying cause when two or more causes are reported. He is requested to report in Part I on line (a) the immediate cause of death and the antecedent conditions on lines (b), (c), and (d) which gave rise to the cause reported on

I (a), the underlying cause being stated lowest in the sequence of events. However, no entry is necessary on I(b), I(c), or I(d) if the immediate cause of death, stated on I(a) describes completely the sequence of events. If the decedent had more than four causally related conditions relating to death, the certifier is requested to add lines (e), (f), etc., so all conditions related to the immediate cause of death are entered in Part I with only one condition to a line.

Any other significant condition which unfavorably influenced the course of the morbid process and thus contributed to the fatal outcome but not resulting in the underlying cause given in Part I is entered in Part II.

EXCERPT FROM U.S. STANDARD CERTIFICATE OF DEATH (Rev.11/2003)

In the following example, there are three causes reported. On line I(c) the underlying cause is entered-congenital heart disease. Congenital heart disease gave rise to congestive heart failure (line I(b)) which in turn led to a myocardial infarction (line I(a)) — the immediate cause of death.

            I    (a) Myocardial infarction

                 (b) Congestive heart failure

                 (c) Congenital heart disease

                 (d)

            II

As demonstrated by the following example, the certifier may not always list one cause per line:

            I    (a) Myocardial infarction and pulmonary embolism with congestive heart failure

                 (b)

                 (c)

                 (d)

            II

Likewise, the causes may not be reported in an acceptable sequence. In the following example, cancer is reported as due to diabetes.

            I    (a) Cancer

                 (b) Diabetes

                 (c)

                 (d)

            II

To date, the causes of the majority of cancers are still unknown so the causal relationship tables stored in the NCHS computers preclude the assumption that diabetes caused the cancer. Cancer is selected as the underlying cause of death from this certification for statistical purposes. However, the selection of the underlying cause of death is not relevant for this manual. For coding purposes, the order and position of each cause of death reported on the death certificate must be interpreted accurately so the computer software can then determine the correct underlying cause of death.

There is an average of three causes listed per certificate. Approximately 20 percent have only one cause of death and 45 percent have three or more causes. Frequently, a cause will be reported on I(a) in Part I and a cause in Part II with no other reported causes. For other records, several causes may all be reported on a single line of the certificate or they may be entered on several lines in Part I. Rarely, the only cause(s) reported may be in Part II. Representative examples follow.

            I    (a) Pneumonia

                 (b)

                 (c)

                 (d)

            II  Diabetes

            I    (a) Cancer

                 (b)

                 (c)

                 (d)

            II

            I    (a)

                 (b)

                 (c)

                 (d)

            II Diabetes

            I    (a)

                 (b) Acute myocardial infarction

                 (c)

            II Renal disease

            I    (a) AMI, renal disease, pulmonary embolism