4Diagnostic Coding:

Introduction to ICD-9-CM and ICD-10-CM

Learning Outcomes

When you finish this chapter, you will be able to:4.1 Discuss the purpose of the ICD-9-CM.4.2 Compare ICD-9-CM Volumes 1, 2, and 3.4.3 Summarize the structure, content, and the five

conventions that are followed in the Alphabetic Index.4.4 Summarize the structure, content, and ten

conventions that are followed in the Tabular List.4.5 Recognize the chapters that make up the Tabular

List.4.6 Identify the purpose and correct use of V codes and

of E codes.

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Learning Outcomes (Continued)

When you finish this chapter, you will be able to:4.7 List the five steps in the process of assigning

diagnosis codes.4.8 Describe and provide examples of three key coding

guidelines that are included in the ICD-9-CM Official Guidelines for Coding and Reporting.

4.9 Explain five differences and two similarities between ICD-10-CM and ICD-9-CM.

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Key Terms

• acute• addenda• adverse effect• Alphabetic Index• category• chief complaint (CC)• chronic• coexisting condition• combination code• convention• crosswalk

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• diagnostic statement• E code• eponym• etiology• ICD-9-CM• ICD-9-CM Official

Guidelines for Coding and Reporting

• ICD-10-CM• late effect• main term

Key Terms (Continued)

• manifestation• NEC (not elsewhere

classified)• NOS (not otherwise

specified)• primary diagnosis• subcategory• subclassification• subterm• supplementary term• Table of Drugs and

Chemicals

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• Tabular List• unspecified• V code

4.1 The ICD-9-CM 4-6

• The diagnosis codes used in the United States are based on the International Classification of Diseases (ICD)

• The U.S. version of the ninth edition is called the ICD-9’s Clinical Modification, or ICD-9-CM– Used to code and classify morbidity data from

patient medical records, physician offices, and surveys

• Addenda—updates to the ICD-9-CM

4.2 Organization of the ICD-9-CM 4-7

• The ICD-9-CM has three parts (or volumes):1. Diseases and Injuries: Tabular List—Volume 1:

Tabular List—section of the ICD-9-CM listing diagnosis codes numerically

2. Diseases and Injuries: Alphabetic Index—Volume 2: Alphabetic Index—section of the ICD-9-CM listing diseases and injuries with corresponding diagnosis codes alphabetically

3. Procedures: Tabular List and Alphabetic Index—Volume 3: covers procedures chiefly in hospitals+

4. http://icd9cm.chrisendres.com/index.php

4.3 The Alphabetic Index 4-8

• The Alphabetic Index:– Contains all the medical terms in the Tabular List

classifications– Organized by the condition, not body part– Medical term describing the condition for which a

patient is receiving care is located in the physician’s diagnostic statement—a physician’s description of the main reason for a patient’s encounter

4.3 The Alphabetic Index (Condition) 4-9

• Main term—boldfaced entry that identifies a disease or condition in the ICD-9-CM Alphabetic Index

• Subterm—word or phrase that describes a main term in the ICD-9-CM Alphabetic Index

• Etiology—cause or origin of a disease• Supplementary term—nonessential word or phrase

that helps define a code in the ICD-9-CM• Convention—typographic techniques or standard

practices that provide visual guidelines for understanding printed material

4.3 The Alphabetic Index (Condition) 4-10

• NEC (not elsewhere classified)—indicates the code to use when an illness or condition cannot be placed in any other category

• Manifestation—characteristic sign or symptom of a disease

• Combination code—single code that classifies both the etiology and the manifestation of an illness or injury

• Eponym—name or phrase formed from or based on a person’s name

4.3 The Alphabetic Index (Continued) 4-11

• Five conventions apply to using the Alphabetic Index correctly:1. Turnover lines are indented farther to the right than

subterms2. See cross-references lead the coder to another main

term; see also suggest additional possible key terms3. Notes provide information on code selection4. The abbreviation NEC appears with main terms for

which no specific code exists5. Some conditions may require two codes