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ICD-10: FAQs

The federal government has postponed the implementation of ICD-10 codes in all billing activities pursuant to the Protecting Access to Medicare Act of 2014, House Resolution 4302, Section 212, Delay in Transition from ICD-9 to ICD-10 Code Sets:

“The Secretary of Health and Human Services may not, prior to October 1, 2015, adopt ICD-10 code sets as the standard for code sets under section 1173(c) of the Social Security Act (42 U.S.C. 1320d-2(c)) and section 162.1002 of title 45, Code of Federal Regulations.”

On July 31, 2014, the Centers for Medicare & Medicaid Services (CMS) released a final rule that will require ICD-10 to be implemented on October 1, 2015, and that will require HIPAA-covered entities to continue to use ICD-9 until September 30, 2015.


  1. What does International Classification of Diseases, 10th Revision (ICD-10) compliance mean?

    ICD-10 compliance means that all HIPAA-covered entities are able to successfully conduct health care transactions on or after October 1, 2015, using the ICD-10 diagnosis and procedure codes. ICD-9 diagnosis and procedure codes can no longer be used for health care services provided on or after this date.

  2. Why is the ICD-10 transition necessary?

    ICD-10 is a provision of HIPAA, as regulated by the U.S. Department of Health and Human Services (HHS), Centers for Medicare & Medicaid Services (CMS). This federal mandate pertains to all HIPAA-covered entities.

    The transition from ICD-9 to ICD-10 is occurring for the following reasons:

      • ICD-9 codes have limited data about patient’s medical conditions and hospital inpatient procedures.
      • ICD-9 codes use outdated and obsolete terms and are not consistent with current medical practices.

    The structure of ICD-9 limits the number of new codes that can be created, and many ICD-9 categories are full. A successful transition to ICD-10 is vital to transforming our nation’s health care system.

  3. Codes change every year, so why is the transition to ICD-10 any different from the annual code changes?

    ICD-10 codes are different from ICD-9 codes in several ways. Currently, ICD-9 codes are for the most part numeric and have three to five digits. ICD-10 codes are alphanumeric and contain three to seven characters. ICD-10 codes provide a higher level of description. However, like ICD-9 codes, ICD-10 codes will be updated every year.

  4. Will ICD-10 replace Current Procedural Terminology (CPT) procedure coding?

    No. The transition to ICD-10 does not affect CPT coding for outpatient procedures. For hospital inpatient procedures, ICD-9 codes will be transitioned to ICD-10-PCS (Procedure Coding System).

  5. What is the implementation date for ICD-10?

    On October 1, 2015, medical coding in U.S. health care settings will change from ICD-9 code sets to ICD-10 code sets.

  6. After the October 1, 2015, implementation date, when do I use ICD-9 versus ICD-10 on my claim?

    Please refer to the chart below, using the date specified in the date field, to determine the ICD code version to use. If the value of the date field is before October 1, 2015, use ICD-9 to code the diagnosis. If the value of the date field is on or after October 1, 2015, use ICD-10.

    Claim Type Claims Date Field To Be Used For Determining ICD Code Version
    1 Pharmacy Date of service
    2 Long Term Care (LTC) Through date
    3 Inpatient Through date
    4 Outpatient From date
    5 Medical From date
  7. Will there be a grace period for converting to ICD-10?

    No.

  8. How is Medi-Cal addressing the implementation of ICD-10?

    Medi-Cal will be using a crosswalk solution in the legacy California Medicaid Management Information System (CA-MMIS). Medi-Cal has mapped all ICD-10 codes to corresponding ICD-9 codes starting with the General Equivalence Mappings (GEMs) provided by the Centers for Medicare & Medicaid Services (CMS) and modifying the mappings to align with existing Medi-Cal policy. Claims will be run against the crosswalk to determine the ICD-9 value to process through the system. The crosswalk will only be used temporarily for ICD-10 claim adjudication while the implementation of our new MMIS system is being completed. Once the new system is online, Medi-Cal will adjudicate all claims natively using ICD-10 and the crosswalk will no longer be used.

  9. What is a crosswalk solution?

    Medi-Cal has mapped all ICD-10 codes to corresponding ICD-9 codes starting with the General Equivalence Mappings (GEMs) and Reimbursement Mappings provided by the Centers for Medicare & Medicaid Services (CMS) and modifying the mappings to align with existing Medi-Cal policy. Claims that are submitted with ICD-10 starting October 1, 2015, will run against this crosswalk in order to identify the appropriate ICD-9 code that will be used to process the claim. The crosswalk will only be used temporarily for ICD-10 claim adjudication while the implementation of our new MMIS system is being completed. Once the new system is online, Medi-Cal will adjudicate all claims natively using ICD-10 and the crosswalk will no longer be used.

  10. Will an ICD-10 to ICD-9 crosswalk be published?

    Medi-Cal will not publish the crosswalk. The crosswalk will not be published since there is already a process for appeal of claim adjudication where there are disagreements between the amount paid and the amount submitted. However, the provider manuals will be updated with the ICD-10 codes as appropriate, allowing providers to refer to the manual for guidance.

  11. Who is affected by the transition to ICD-10? If I don’t deal with Medicare claims, will I have to transition?

    Everyone covered by HIPAA must transition to ICD-10. This includes providers and payers who do not deal with Medicare or Medicaid claims.

  12. What if I don’t make the transition to ICD-10?

    For HIPAA-covered entities, transition to ICD-10 is not an option. Claims for all services and hospital inpatient procedures performed on or after the compliance deadline must use ICD-10 diagnosis and inpatient procedure codes. This change does not apply to Current Procedural Terminology (CPT) coding for outpatient procedures. Without ICD-10, providers will experience delayed payments or even non-payments; increased rejected, denied or pending claims; reduced cash flows and ultimately lost revenues.

    It is important to note, however, that claims for services and inpatient procedures provided before the compliance date must use ICD-9 codes.

  13. Is Medi-Cal policy going to change with ICD-10?

    Medi-Cal will be updating the provider manuals to account for the change to ICD-10 in 2015. However, due to the size of the ICD-10 code set and limitations in the legacy MMIS, policy will not change.

  14. Will Medi-Cal accept claims with both ICD-10 and ICD-9 codes on the same claim form?

    No. Medi-Cal will accept claim forms containing only ICD-9 or ICD-10 codes.

  15. If I transition early to ICD-10, will Medi-Cal be able to process my claims?

    Pursuant to the CMS final rule issued on July 31, 2014: “This final rule implements section 212 of the Protecting Access to Medicare Act of 2014 by changing the compliance date for the International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM) for diagnosis coding, including the Official ICD-10-CM Guidelines for Coding and Reporting, and the International Classification of Diseases, 10th Revision, Procedure Coding System (ICD-10-PCS) for inpatient hospital procedure coding, including the Official ICD-10-PCS Guidelines for Coding and Reporting, from October 1, 2014 to October 1, 2015. It also requires the continued use of the International Classification of Diseases, 9th Revision, Clinical Modification, Volumes 1 and 2 (diagnoses), and 3 (procedures) (ICD-9-CM), including the Official ICD-9-CM Guidelines for Coding and Reporting, through September 30, 2015.”

    Medi-Cal will transition to the use of ICD-10 on October 1, 2015, and early or late transitions will not be allowed.

  16. Are paper claims affected by the transition to ICD-10?

    Yes. All claim transactions, whether paper or electronic, except dental claims, will be required to be submitted using ICD-10 codes.

  17. What type of training will providers and staff need for the ICD-10 transition?

    Medi-Cal will be providing education about the use of ICD-10 for submitting claims to Medi-Cal. Providers are encouraged to visit the Medi-Cal website regularly throughout the course of the transition to access the latest information about education opportunities.

    In addition, ICD-10 resources and training materials may be available through the Centers for Medicare & Medicaid Services (CMS), many professional associations and societies, and software/system vendors.

  18. Do Treatment Authorization Requests (TAR) or Service Authorization Requests (SAR) that have been approved prior to October 1, 2015, with approval extending past October 1, 2015, need to be resubmitted with ICD-10-CM diagnosis codes?

    No. All active TARs/SARs based on the submission of ICD-9 before October 1, 2015, that span the ICD-10 implementation date will remain valid. Claims containing ICD-10 in adherence with the ICD-10 implementation rules will not be negatively impacted by the ICD-9 TAR/SAR approvals.
  19. When claims are submitted after October 1, 2015, with ICD-10-CM diagnosis codes, for services dated after October 1, 2015, will there be an impact to claims if the ICD codes versions used (i.e., ICD-10-CM or ICD-9-CM) do not match on the claim and on the TAR/SAR (for example, a TAR/SAR with ICD-9-CM diagnosis codes and a claim with ICD-10-CM diagnosis codes)?

    No. All active TARs/SARs based on the submission of ICD-9 before October 1, 2015, that span the ICD-10 implementation date will remain valid. Claims containing ICD-10 in adherence with the ICD-10 implementation rules will not be negatively impacted by the ICD-9 TAR/SAR approvals.

  20. Will Treatment Authorization Requests (TAR) or Service Authorization Requests (SAR) require ICD-10-CM diagnosis codes on October 1, 2015?

    Yes. Any TAR/SAR currently requiring an ICD-9-CM diagnosis code will require an ICD-10-CM diagnosis code on or after October 1, 2015.

  21. Medi-Cal is proceeding with system changes to prepare for ICD-10. As a submitter, what changes can I expect prior to October 1, 2015?

    Effective September 22, 2014, all claims submitted on the CMS-1500, UB-04, 25-1, 30-1, and 30-4 will require the entry of an ICD Code indicator on the claim form specifying the submission of ICD-9 or ICD-10 with the exception of the Confidential Screening/Billing Report (PM 160) claim form, which will not include an indicator. Submitters are expected to provide ICD-9 codes and use the ICD-9 indicator on claims until the transition to ICD-10 on October 1, 2015.

    A “0” will indicate the claim was submitted with ICD-10 codes. A “9” will indicate ICD-9 codes.

    Also effective September 22, 2014, all electronic TARs (eTAR) forms will require the inclusion of the ICD code indicator and ICD code. Paper TARs submitted on 18-1, 18-2, 18-3, 20-1, 50-1, 50-2, and 50-3 will require an ICD code on the submission. A diagnosis description in lieu of the diagnosis code will no longer be accepted on eTAR or paper TAR submissions.

  22. Can I request a re-authorization TAR/SAR with ICD-9-CM diagnosis codes on or after October 1, 2015?

    No. Requests on or after October 1, 2015, for re-authorization of a TAR/SAR currently containing ICD-9-CM/Volume 3 codes will require a new TAR/SAR request containing ICD-10-CM/PCS codes.

  23. Are APR-DRG claims using the Medi-Cal defined ICD-10 to ICD-9 Backward Map crosswalk to group claims to determine the appropriate DRG pricing code?

    No. All patient refined diagnosis related groups (APR-DRG) claims are processed differently than other Medi-Cal claims. Medi-Cal uses the 3M Corporation APR-DRG module to group APR-DRG claims. The 3M Corporation APR-DRG module receives the submitted ICD-10-CM diagnosis code (for dates of service/dates of discharge on or after October 1, 2015) and uses these codes according to the 3M grouping logic to provide a DRG code.

  24. When and how will ICD-10 affect the DRG payment method? (Question #29 from the Medi-Cal DRG Payment Method Frequently Asked Questions for FY 2015-16 on the DHCS website)

    Nationwide ICD-10 implementation is expected October 1, 2015. At that time, the Medi-Cal claims processing system will accept ICD-10-CM/PCS codes and will utilize ICD-10 codes for internal processing. ICD-10-CM/PCS codes will be mapped to ICD-9-CM/Volume 3 codes using the 3M APR-DRG mapper and then the DRG will be assigned. Hospitals should follow national guidelines in submitting ICD-10 codes to Medi-Cal.

  25. Does the fact that Medi-Cal is using a crosswalk to adjudicate claims mean that Medi-Cal is not ready for the ICD-10 implementation or is non-compliant with the Federal ICD-10 mandate?

    No. Medi-Cal is ready to process Medicaid claims containing ICD-10-CM/PCS codes. Medi-Cal successfully implemented system changes for ICD-10 in September 2014, and has been ready to receive ICD-10-CM/PCS codes since that implementation.

    CA-MMIS is ready and fully compliant with the CMS requirement to accept only ICD-10-CM/PCS codes for claims with dates of service/dates of discharge on or after October 1, 2015

  26. Has CMS approved the Medi-Cal’s crosswalk solution?

    Yes. CMS approved the Medi-Cal crosswalk for implementing ICD-10. In July 2013, Medi-Cal posted ICD-10 FAQ #8 informing the Medi-Cal community and public of Medi-Cal’s intent to use a crosswalk solution.

  27. Why is California using the crosswalk technique?

    Medi-Cal is working on a system replacement effort which, upon implementation, will process natively using ICD-10. As an interim solution, Medi-Cal implemented ICD-10 on its legacy system utilizing a crosswalk in order to reduce the cost and system changes to an aging system which was being replaced. Using a crosswalk allowed for implementation using the current system rules and payment methodology. This approach allowed Medi-Cal to minimize risks and impact to its providers by reducing the chances for payment variances between ICD-9 and ICD-10. The crosswalk value is solely utilized internally within CA-MMIS for the purposes of adjudication of the claims.

    The Medi-Cal crosswalk is not going to be used for DRG grouping purposes. The 3M Corporation APR-DRG module will accept the submitted ICD code, both ICD-9 or ICD-10 based on the date of discharge, to determine a DRG code.

    The submitted ICD-10-CM/PCS code(s) are carried throughout claims processing and are returned in all communications to the provider.

  28. Why won’t Medi-Cal publish the crosswalk used to adjudicate claims?

    Consistent with industry standards for any payer system, Medi-Cal does not release internal system processing rules. Medi-Cal has provided a process to appeal the adjudication of a claim where there are disagreements between the amount paid and the amount submitted. Medi-Cal has conducted significant levels of testing, both internally and externally, as well as continual reviews of the crosswalk and ICD-10 policy to minimize the impacts to providers of the implementation of ICD-10.

    Medi-Cal will be monitoring the MMIS system and claims adjudication closely through the implementation period.

  29. Do I need to do anything special for claims that provide services over the implementation period (on or before September 30, 2015, through or after October 1, 2015)?

    Depending on the services provided and type of claim billed, providers may be required to split bill services with one claim containing ICD-9-CM/Volume 3 codes for services provided up through September 30, 2015, and the second claim containing ICD-10-CM/PCS codes for services provided starting October 1, 2015.

    Medi-Cal has published a detailed ICD-10 Implementation Billing Guide identifying the types of services and claims that need to be split billed.

  30. What can providers do to reduce payment delays?

    In order to decrease the likelihood of delays in claim processing and payment following the ICD-10 implementation on October 1, 2015, providers should verify their billing system and processes:

    • Claims with dates of service/dates of discharge prior to October 1, 2015, contain ICD-9-CM/Volume 3 codes and the ICD indicator is set for ICD-9.
    • Claims with dates of service/dates of discharge on or after October 1, 2015, contain ICD-10-CM/PCS codes and the ICD code indicator is set for ICD-10.
    • Reviewed the updated provider manuals for ICD-10 on the Medi-Cal website.
  31. Can I submit both the ICD-9 and ICD-10 coded claims in the same file?

    Yes. A claim file may contain claims coded with ICD-9 and Claims coded with ICD-10 in the same electronic claims submission file. However, as single claim containing both ICD-9 and ICD-10 codes will not be accepted.

  32. Where can I get additional information about ICD-10?

    More information about ICD-10 is available on the ICD-10 Web page of the CMS website.