Skip to Main content

ICD-10 Resource Center

What is ICD-10?

ICD-10-CM is the United States' clinical modification of the World Health Organization's (WHO) International Classification of Diseases (ICD) 10th Revision. It is used to classify diseases and causes of illness recorded on health records, claims, and other vital information. ICD-10-PCS is the procedure classification system used to report hospital inpatient procedures.

The U.S. Department of Health and Human Services ("HHS") issued a ruling in 2009 that required covered entities (health plans, health care providers, and health care clearinghouses) that conduct electronic HIPAA standard transactions to move from ICD-9 to the next generation ICD-10 code sets by October 1, 2014. However, with the enactment of the Protecting Access to Medicare Act of 2014, the Secretary of Health and Human Services may not, prior to October 1, 2015, adopt ICD-10 code sets. The Centers for Medicare and Medicaid Services (CMS) is examining the implications of the ICD-10 provision and will provide guidance to providers and stakeholders soon. The transition does not affect the Current Procedural Terminology (CPT®) code set, which will continue to be used for outpatient services.

Differences between ICD-9 and ICD-10

ICD-9-CM and ICD-10-CM (Clinical Modification)

  • ICD-9-CM and ICD-10-CM have the same hierarchical structure; however, there are changes in the organization of the code set.
  • ICD-10-CM allows for more characters (from three to seven) and requires a decimal point.
  • ICD-10-CM codes are alphanumeric, which adds laterality and provides a greater level of specificity.

ICD-9-PCS and ICD-10-PCS (Procedure Coding System)

  • ICD-10-PCS codes have been completely revised.
  • ICD-10-PCS codes are always seven characters and decimal points are not used. ICD-10-PCS codes are alphanumeric.
  • ICD-10-PCS codes are constructed through the assignment of characters, each representing an aspect of the inpatient procedure.
  • Generally, ICD-10-CM and ICD-10-PCS allow for a higher level of specificity over the ICD-9 code set.

Other Key Information:


  • August 2015 Eye on ICD-10: (PDF) Dates of service and impact on prior authorizations
  • June 2015 Eye on ICD-10: (PDF) ICD-10 readiness testing
  • May 2015 Eye on ICD-10: (PDF) Avoid claim delays; understand ICD-10 claim splitting guidelines
  • April 2015 Eye on ICD-10: (PDF) Preparing your vendors for ICD-10
  • March 2015 Eye on ICD-10: (PDF) Getting ready for ICD-10

Contact Us

If you have additional questions about AmeriHealth Caritas' transition to ICD-10, please submit your questions using our secure contact form.

Note: Be sure to select "Provider ICD 10 Questions" from the Subject dropdown box.