Differences between ICD-9 and ICD-10 coding systems

Transition to ICD-10-CM/PCS

The International Classification of Diseases (ICD) is used by health organizations globally to track disease incidence and prevalence (WHO, 2012). ICD is also used in some countries to manage healthcare reimbursement and resource allocation, including the United States. The ICD has undergone periodic revisions to keep abreast of the constantly changing health conditions of populations, advances is detection and treatment of diseases, and the healthcare management needs of countries. In the United States, the current version, ICD-9, is scheduled to be replaced by ICD-10 on October 1, 2013 (CMS, 2010). In May 1990, ICD-10 was endorsed by the 43rd World Health Assembly and began to be implemented in member states as early as 1994 (WHO, 2012). The next revision, ICD-11, is currently being prepared and will probably be ready for endorsement by 2015.

Purpose of ICD-10-CM/PCS

In the United States, the ICD-10 nomenclature is appended with -CM/PCS, which stands for Clinical Modification/Procedure Coding System (CMS, 2010). This nomenclature represents the existence of two code sets, one for disease diagnosis (ICD-10-CM) and the other for inpatient procedures (ICD-10-PCS). The diagnosis code set is for use in all health care settings, while use of the inpatient code set will be limited to hospitals. The transition to ICD-10-CM/PCS is mandatory for any organization covered by the Health Insurance Portability and Accountability Act (HIPAA) of 1996.

The most obvious change from ICD-9-CM to ICD-10-CM/PCS will be longer codes, from 3 to 5 in ICD-9-CM, to 3 to 7 (CM) and 7 (PCS) (CMS, 2010). The longer codes represent the expanded needs of health care providers, due to the medical advances that have occurred during the 30-year history of ICD-9 use. The older code set contains outdated terminology, little to no room for expansion, and in some cases no longer represents current practice guidelines.

Impact of the Transition to ICD-10-CM/PCS

The transition to ICD-10-CM/PCS began on January 1, 2012 with the upgrade of the transaction standards for electronic health care claims from Version 4010/4010A to 5010 (CMS, 2010). Since this transition covers all claims processed electronically, this affects all HIPAA covered health care clinics, hospitals, doctor offices, providers, payers, billing services, and healthcare clearinghouses. By October 1, 2013, all HIPAA covered organizations must be using ICD-10-CM/PCS.

The clinical impact of ICD-10-CM/PCS is expected to be greater accuracy describing the medical conditions encountered by care professionals, reduced redundancy, improved patient outcomes, less medical errors, and improved research results due to the higher quality and greater specificity of health data (Sanders et al., 2012, p. 2). In a post-9/11 America, the improved coding accuracy may also help to identify bioterrorism and other public health threats earlier.