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ICD-9, which is over 30 years old, is currently used for reporting health care diagnosis codes in the United States. ICD-10-CM is the diagnosis classification system developed by the Centers for Disease Control and Prevention and is currently used in many countries. Diagnosis coding under this system uses a different number of digits and some other changes, but the format is very similar to ICD-9-CM.

ICD-10 Compliance Date

The U.S. Department of Health and Human Services (HHS) issued a rule finalizing Oct. 1, 2015 as the new compliance date for health care providers, health plans, and health care clearinghouses to transition to ICD-10, the tenth revision of the International Classification of Diseases. This deadline allows providers, insurance companies and others in the health care industry time to ramp up their operations to ensure their systems and business processes are ready to go on Oct. 1, 2015.

The rule External link requires the use of ICD-10 beginning October 1, 2015. The rule will also require HIPAA covered entities to continue to use ICD-9-CM through September 30, 2015.

Stay up to date on ICD-10!

Sign up for CMS ICD-10 Industry Email Updates External link

ICD-9 vs. ICD-10 Billing Guidelines Effective October 1

  • ICD-10 implementation is date of service driven
  • Claims cannot contain both ICD-9 and ICD-10 diagnosis codes on same claim, such claims will Returned to Provider (RTP)
  • Claims cannot contain both ICD-9 and ICD-10 procedure codes on same claim, such claims will RTP
  • Claims submitted with date(s) of service prior to October 1, 2015, must contain appropriate ICD-9 code(s)
  • Claims with date(s) of services on/after October 1, 2015, must contain appropriate ICD-10 code(s) only. If a claim includes an ICD-9 code, it will RTP as unprocessable. Providers must submit a new claim that contains appropriate ICD-10 code(s)
  • Split Claims – Will require providers to split claims so all ICD-9 codes remain on one claim with dates of service through September 30, 2015 and all ICD-10 codes placed on another claim with DOS beginning October 1, 2015 and later

The CMS Medicare Learning Network (MLN) Special Edition (SE)1408 External link provides guidance for claims that span the ICD-10 implementation date. We encourage providers to share this information all staff.


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Providers can keep informed of ICD-10 implementation activities by registering for the Noridian Email list.

Last Updated Apr 13, 2017

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