The International Statistical Classification of Diseases and Health Related Problems (ICD), now in its tenth revision, has become the international standard diagnostic classification for all general epidemiological and many health management purposes. Originally designed to classify causes of death, the application of the classification to morbidity statistics has expanded with each subsequent revision. The United States and a number of other countries, however, continue to find it necessary to develop clinical modifications of the ICD to meet the needs of their respective healthcare systems that require more detailed clinical information from hospital, clinic and physician records.


The clinical modification of ICD-9 (ICD-9-CM, Volumes 1 and 2) is adopted in the United States in 1979 for morbidity applications, at the same time that ICD-9 (published by WHO) is adopted for mortality data. No rulemaking is required.

ICD-10-CM Development Timeline


The Tenth Revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-10) is first released by the World Health Organization (WHO).


National Committee on Vital and Health Statistics (NCVHS) sends a letter to the Assistant Secretary for Health urging the Department to consider the desirability and feasibility of developing a clinical modification of ICD-10 for morbidity purposes.

NCHS awards a contract to the Center for Health Policy Studies to evaluate ICD-10 for morbidity uses within the United States. A prototype of ICD-10-CM is developed following a thorough evaluation of ICD-10 by a Technical Advisory Panel (TAP) consisting of private and public sector stakeholders. The TAP concludes that there are compelling reasons for recommending an improved clinical modification of ICD-10 that would overcome most limitations of ICD-10 for morbidity applications. The TAP strongly recommends that NCHS proceed with implementation of a revised version of ICD-10-CM.


Further work on ICD-10-CM is undertaken by NCHS, including a thorough review of ICD-9-CM Coordination and Maintenance Committee proposals for modifications that could not be incorporated into ICD-9-CM and extensive collaboration with many medical/surgical specialty groups.

HCFA awards a contract to 3M HIS to develop the procedure classification system to replace Volume 3 of ICD-9-CM (hospital inpatient procedures). A Technical Advisory Panel provides review and comments throughout the development. The new procedure classification adheres to the criteria established by NCVHS for a procedure classification system in 1993.


The draft of the Tabular List of ICD-10-CM, and the preliminary crosswalk between ICD-9-CM and ICD-10-CM is made available on the NCHS website for public comment during a three-month open comment period, which begins December 1997 and ends February 1998. More than 1,200 comments are received from 22 individuals and organizations representing a variety of groups, including one governmental agency, two research institutions, three information system developers, four professional organizations, and several health care providers. Comments range from general observations to very specific and detailed analyses.

Clinical Data Abstraction Centers conduct formal testing of ICD-10-PCS.


Additional formal testing is conducted for ICD-10-PCS, using ambulatory records.

Final version of ICD-10-PCS, training materials and crosswalk to ICD-9-CM procedure codes is posted on CMS website.


More than eight days of hearings are held by NCVHS with letters and written and oral testimonies provided by more than 80 public and private sectors groups representing the healthcare industry, the Federal and State governments, public health and research communities, insurers, and providers.


ICD-10 is implemented in the United States for mortality reporting.

An overview of the comments received during the ICD-10-CM comment period is posted on the NCHS website in 1999. A summary of the comments also is presented at the November 1999 ICD-9-CM Coordination and Maintenance Committee meeting and posted on NCHS website.


The Notice of Proposed Rulemaking (NPRM) for Transactions and Code sets is published by the Department, as required by the Health Insurance Portability and Accountability Act of 1996. ICD-9-CM is proposed as the initial standard for diagnoses and inpatient procedures. The NPRM includes the following language: In addition to accommodating the initial code sets standards for the year 2000, those that produce and process electronic administrative health transactions should build the system flexibility that will allow them to implement different code formats beyond the year 2000.


The Final Rule for Transactions and Code Sets is published and states: ICD-10-CM has great potential for replacement of ICD-9-CM.


Further enhancements to ICD-10-CM continue with changes being made in response to the open comment period, as well as, input from physician specialty groups.


The American Health Information Management Association (AHIMA) and the American Hospital Association (AHA) jointly conduct a pilot test of ICD-10-CM during June/July 2003. The study involves dual coding records in ICD-9-CM and ICD-10-CM. More than 6100 records from a broad cross section of health care community were dual coded by 180+ participants. The results indicated that: there is general support for adoption of ICD-10-CM; ICD-10-CM is seen as an improvement over ICD-9-CM; and ICD-10-CM is more applicable to non-hospital settings than ICD-9-CM. NCVHS commissions a cost-benefit analysis on implementation of ICD-10-CM and ICD-10-PCS by the Rand Corporation. Blue Cross Blue Shield Association commissions Robert E. Nolan Company to prepare an alternate cost analysis; the Nolan study does not attempt to quantify benefits.

NCVHS sends a letter to the Secretary recommending replacement of ICD-9-CM with ICD-10-CM and ICD-10-PCS and initiation of the regulatory process ( ).


ICD-10-CM is updated annually every October 1 to accommodate changes made to ICD-10 by WHO and to incorporate changes made to ICD-9-CM diagnosis codes. ICD-10-PCS is updated annually every October 1 to incorporate changes made to ICD-9-CM, Volume 3.


NCVHS sends a letter to the Secretary titled, “Revision to HIPAA Transaction Standards Urgently Needed.” The letter states that “…there are specific and urgent business drivers (e.g., the need to accommodate ICD-10 codes) that justify adoption of Version 5010.


In a letter to the Secretary on “Quality measurement and public reporting in the current health care environment”, NCVHS recommends that the Department “Accelerate US adoption of ICD-10-CM and ICD-10-PCS by publishing the required notice of proposed rulemaking.”

The Department publishes a Notice of Proposed Rulemaking for replacement of ICD-9-CM by ICD-10-CM and ICD-10-PCS on October 1, 2011.


The Department publishes a final rule for adoption of ICD-10-CM and ICD-10-PCS by October 1, 2013.


NCVHS conducts a hearing on implementation of updated versions of the HIPAA transaction standards and ICD-10 code sets. Following the hearing, the Committee sends a letter to the Secretary recommending that HHS, “Reiterate in every publication, presentation and public forum, that the deadline for Versions 5010, D.0 and 3.0 is January 1, 2012, and the deadline for implementation for ICD-10 code sets is October 1, 2013. These deadlines have been established by HHS as the law, and there is no justification for changing them. HHS, through CMS, must effectively publicize its commitment to the compliance dates.”


NCVHS holds another hearing on transition to updated versions of the HIPAA transaction standards and ICD-10 code sets and again recommends to the Department that “HHS should use all communication vehicles to reiterate and emphasize that the compliance dates for implementing 5010/D.0/3.0 and ICD-10 code sets are not changing.”