Go to content

ICD-10 Institutional Newsletters

Date: May 1, 2013

Subject: ICD-10 Introduction

The Transition Institutional Providers’ ICD-10 Resource

ICD-10 Introduction

ICD-10 is a coding system that was adopted by the World Health Organization in 1990 as the international version of diagnostic coding. This coding system is widely utilized (with modifications) internationally. ICD-10-CM is the United States’ version of this code set. All covered entities will be required to use ICD-10 codes for any HIPAA transactions as of October 1, 2014.

ICD-9-CM is the coding system the United States currently uses to report patient conditions. It is over 30 years old and no longer supports industry needs. Limitations of the code set include a lack of specificity conveyed in the codes. Many ICD-9 code chapters are full which impedes the ability to add new codes. The implementation of ICD-10 is expected to address these issues by providing a significant improvement in code specificity. Terminology and disease classification has been updated to be consistent with current clinical practice. Revisions in structure allow greater expandability to accommodate new technology and emerging diseases. It also permits future updates without disruption of the numbering system.

Comparing ICD-9-CM and ICD-10-CM

ICD-10-CM differs from ICD-9-CM in its organization and structure, code composition, and level of detail. Table 1 provides a comparison of the features of the ICD-9 and ICD-10 diagnosis codes sets. Table 2 provides a comparison of the structure and format.

Table 1 - Comparing the Diagnosis Code Sets
3 - 5 characters 3 - 7 characters
Approximately 13,000 codes Approximately 70,000 codes
First digit is numeric or alpha (E or V) First digit is alpha, all letters used except U
Digits 2 - 5 are numeric Digit 2 is numeric; digits 3 - 7 are alpha or numeric
Decimal placed after the first three characters Decimal placed after the first three characters
Limited space for adding new codes Flexible for adding new codes
Lacks detail Greater specificity
Does not distinguish laterality Includes laterality (i.e., codes identifying right vs. left) where appropriate
Table 2 - Comparing the Structure and Format of the Diagnosis Code Sets
ICD-9-CM Code Format ICD-10-CM Code Format

Examples of ICD-10-CM codes:

  • A69.21 - Meningitis due to Lyme Disease
  • I25.110 - Arteriosclerotic heart disease of native coronary artery with unstable angina pectoris
  • L89.213 - Pressure ulcer of right hip, stage III
  • O60.12x0 - Preterm labor second trimester with preterm delivery second trimester, not applicable or unspecified
  • T39.013A - Poisoning by aspirin, assault; initial encounter

Comparing ICD-9-PCS and ICD-10-PCS

The ICD-10-PCS is a procedure classification published by the United States for classifying procedures performed in hospital inpatient health care settings. These codes are specific to the United States and not part of any international standards. ICD-10-PCS will replace ICD-9-CM Volume 3 for reporting inpatient procedures, and will be required for all HIPAA transactions effective October 1, 2014. Table 3 demonstrates the dramatic changes in structure, terminology, coding rules, and number of codes. Table 4 outlines the code structure of ICD-10-PCS.

Table 3 - Comparing the Procedure Code Sets
ICD-9-CM Procedure Codes (Vol. 3) ICD-10-PCS Codes
Approximately 4,000 codes Approximately 72,000 codes
Not structure Highly structured
Diagnosis occasionally included Diagnosis not included
NEC and NOS (unspecified and elsewhere classified) are common NEC and NOS are uncommon
Eponyms frequently used Eponyms rarely used
General body locations Detail body locations
Combination codes used frequently Combination codes are rare
Common medical terminology Completely new medical terminology model
Table 4 - Code Structure of ICD-10-PCS
Character 1 2 3 4 5 6 7
Definition Name of Section Body System Root Operation Body Part Approach Device Qualifier

Examples of ICD-10-PCS codes:

  • 0SRD0JZ - Replacement of left knee joint with synthetic substitute, open approach
  • 0FB03ZX - Excision of liver, percutaneous approach, diagnostic
  • 0DP64CZ - Removal of extraluminal device from stomach, percutaneous endoscopic approach

ICD-9-CM’s terminology and classification of numerous conditions and procedures are outdated, vague, and inconsistent. Today’s data needs are significantly different than they were 30 years ago when ICD-9 was introduced. The transition to ICD-10 is necessary because the current coding system can’t keep up with industry changes. The format and structure of ICD-10 allows for expansion as needed and is adaptable to changes in healthcare.

For more information on ICD-10-CM and ICD-10-PCS, see the CMS website at https://www.cms.gov/Medicare/coding/ICD-10.


  • AMA (2010). Fact Sheet 2. The differences between ICD-9 and ICD-10.
  • Barta, Ann; et al.. “ICD-10-CM Primer.” Journal of AHIMA 79, no.5 (May 2008): 64-66
  • Bowman, S. (n.d.). Why ICD-10 is worth the trouble. http://www.ahima.org
  • CMS (2013). ICD-10 Introduction Fact Sheet. http://cms.gov/Medicare/Coding/ICD10
  • Nichols, J. (2010). Health Data Consulting White Paper. ICD-10 A Primer.

Back to ICD-10 Institutional Articles