1. CHAPTER 2
AN OVERVIEW OF ICD-10-CM

2. An Overview of the ICD-10-CM
Classification System
Morbidity (illness)
Mortality (death)
ICD = International Classification of Diseases
WHO’s ICD-10 used globally
World Health Organization
ICD-10-CM = 10th Revision; CM, Clinical Modification
Continuity of data
(Cont’d…)
The International Classification of Diseases, 10th Edition, Clinical Modification (ICD-10-CM) is designed for the classification of patient morbidity and mortality information for statistical purposes and for the indexing of health records by disease and operation for data storage and retrieval.

3. Index Main terms and subterms Figure 2.2
I-10 Index is alphabetic, with the main terms in bold type and subterms indented under the main term.
Figure 2.2
ICD-10-CM Index (From Elsevier: Buck’s 2019 ICD-10-CM Hospital Edition, St. Louis, 2019, Elsevier.)

4. ICD-10-CM Chapters
Chapter 1 Certain Infectious and Parasitic Diseases (A00–B99)
Chapter 2 Neoplasms (C00–D49)
Chapter 3 Diseases of the Blood and Blood-Forming Organs and Certain Disorders Involving the Immune Mechanism
(D50–D89)
Chapter 4 Endocrine, Nutritional, and Metabolic Diseases (E00–E89)
Chapter 5 Mental, Behavioral and Neurodevelopmental Disorders (F01–F99)
Chapter 6 Diseases of the Nervous System (G00–G99)
Chapter 7 Diseases of the Eye and Adnexa (H00-H59)
Chapter 8 Diseases of the Ear and Mastoid Process (H60–H95)
Chapter 9 Diseases of the Circulatory System (I00–I99)
Chapter 10 Diseases of the Respiratory System (J00–J99)
Chapter 11 Diseases of the Digestive System (K00–K95)
Chapter 12 Diseases of the Skin and Subcutaneous Tissue (L00–L99)
Chapter 13 Diseases of the Musculoskeletal System and Connective Tissue (M00–M99)
Chapter 14 Diseases of the Genitourinary System (N00–N99)
Chapter 15 Pregnancy, Childbirth, and the Puerperium (O00–O9A)
Chapter 16 Certain Conditions Originating in the Perinatal Period (P00–P96)
Chapter 17 Congenital Malformations, Deformations, and Chromosomal Abnormalities (Q00–Q99)
Chapter 18 Symptoms, Signs, and Abnormal Clinical and Laboratory Findings, Not Elsewhere Classified (R00–R99)
Chapter 19 Injury, Poisoning, and Certain Other Consequences of External Causes (S00–T88)
Chapter 20 External Causes of Morbidity (V00–Y99)
Chapter 21 Factors Influencing Health Status and Contact with Health Services (Z00–Z99 ) 4

5. Tabular
Figure 2.5
All codes in a chapter begin with a letter.
ICD-10-CM Tabular, R codes. (From Elsevier: Buck’s 2019 ICD-10-CM Hospital Edition, St. Louis, 2019, Elsevier.)
Each section begins with unique letter and codes arranged in numerical order

6. Official Instructional Notations
Includes
Define or give examples of category content
Figure 2.13
I-10 has instructional notations providing guidance to the coder.
All publishers of the I-10 present notations that are part of the official version of the coding system.
Includes notation. (From Elsevier: Buck’s 2019 ICD-10-CM Hospital Edition, St. Louis, 2019, Elsevier.)

7. Excludes1 Excludes1 = Not Coded Here Figure 2.14
What Excludes note is a pure excludes? (Excludes1)
Indicates the code excluded should not be assigned at the same time as the code above the Excludes1 note.
Figure 2.14
Excludes1 notation in I-10. (From Elsevier: Buck’s 2019 ICD-10-CM Hospital Edition, St. Louis, 2019, Elsevier.)

8. Excludes2 Excludes2 = Not Included Here Figure 2.15
Excludes2 note indicates the condition excluded is not part of the condition it is excluded from and a patient may have both conditions at the same time.
When Excludes2 note appears under a code, acceptable to report code and the Excludes2 code together.
Figure 2.15
Excludes2 notation. (From Elsevier: Buck’s 2019 ICD-10-CM Hospital Edition, St. Louis, 2019, Elsevier.)

9. Code First/Use Additional Code
Code First/Use Additional = Etiology/Manifestation Paired Codes
I-10 has a coding conversion that requires the underlying condition to be sequenced first followed by the manifestation.
Figure 2.16
I-10 Tabular, Code first notation. (From Elsevier: Buck’s 2019 ICD-10-CM Hospital Edition, St. Louis, 2019, Elsevier.)

10. Code Also Code Also = More than 1 code required Figure 2.18
Sequencing of the two codes depends on the following:
Severity of the condition.
Reason for the encounter.
I-10 Tabular, Code also notation (From Elsevier: Buck’s 2019 ICD-10-CM Hospital Edition, St. Louis, 2019, Elsevier.)

11. 7th Character and Placeholder X
Codes <6 characters that have a 7th character requirement, X is placeholder
Placeholder X is assigned for all characters less than 6 that require a seventh character.
Figure 2.20
X as the placeholder. (From Elsevier: Buck’s 2019 ICD-10-CM Hospital Edition, St. Louis, 2019, Elsevier.)

12. GEMs Files (1 of 2) ICD-9-CM codes mapped to new ICD-10-CM codes
Figure 2.21
GEMs mapping files I-9 to I-10
(Courtesy U.S. Department of Health and Human Services, Centers for Disease Control and Prevention.) 
GEMs files do not contain decimal points within the codes. For example, in the GEMs file for I-9 code is 0011 and for I-10 code A00.1 is A001.
In Figure 2.21, column 1 displays I-9 codes and column 2 displays I-10 codes.
ICD-9-CM codes mapped to new ICD-10-CM codes

13. GEMs Files (2 of 2) ICD-10-CM codes mapped to ICD-9-CM codes
In Figure 2.22, column 1 displays I-10 codes and column 2 displays I-9 codes.
Figure 2.22
GEMS mapping files I-10 to I-9 (Courtesy U.S. Department of Health and Human Services, Centers for Disease Control and Prevention.)

14. GEMs Flag (Column 3) Three types of flags Approximate No Map
Direct match from I-9 to I-10
Flags: and 10000
No Map
No diagnosis code available
Combination
Requires a combination of codes to map from one system to another
Column 3 of the GEMs file displays flags.
There are five times more codes in the I-10 (69,000+) than in the I-9 (14,000+).
I-9 code may be linked to more than one I-10 code.
Approximate, Flag 1, assists by identifying those times when more than one I-10 code is available to replace an I-9 code.

15. Conclusion CHAPTER 2 AN OVERVIEW OF ICD-10-CM15