ICD-10 frequently asked questions


  • 1. What is ICD-10? ICD-10 stands for the International Classification of Diseases, 10th Edition. ICD is the international standard for diagnostic classifications. The current version, ICD-9, was adopted in 1979. ICD codes are medical codes that provide a detailed representation of a patient’s conditions or diagnoses. ICD-10-CM (clinical modification) codes are diagnosis codes, and ICD-10-PCS (procedure coding system) codes are for hospital inpatient procedures.
  • 2. What does ICD-10 compliance mean? An entity covered by the Health Insurance Portability and Accountability Act (HIPAA) must be able to successfully conduct health care transactions using ICD-10 diagnosis and procedure codes. ICD-9 diagnosis and inpatient procedure codes cannot be used for services provided on or after the Centers for Medicare & Medicaid Services (CMS) implementation date of Oct. 1, 2015.
  • 3. What is the primary purpose of this change? The primary purpose of the ICD-10 implementation is to improve clinical communication. ICD-10 allows for the capture of data regarding signs, symptoms, risk factors and comorbidities to better describe the clinical issue overall. The transition to ICD-10 coding will enable the United States to exchange information across international borders.
  • 4. What are the differences between ICD-9 and ICD-10? ICD-10 replaces ICD-9-CM clinical modification diagnosis codes and ICD-9-PCS procedure codes. The diagnosis codes for ICD-9 are three to five digits which are primarily numeric and combine to make more than 14,000 unique diagnosis codes. ICD-10 diagnosis codes are three to seven alphanumeric digits that combine to make more than 69,000 unique diagnosis codes. ICD-9 procedure codes are three to four numeric digits that combine to make about 4,000 unique procedure codes. ICD-10-PCS (inpatient) procedure codes are seven alphanumeric digits that combine to make approximately 72,000 unique procedure codes. Physicians will still use Current Procedural Terminology (CPT®) codes to report procedures.
  • 5. Who is affected by the transition to ICD-10? All entities covered by HIPAA must transition to ICD-10. This includes Medicare, Medicaid and commercial lines of business.
  • 6. How is the transition to ICD-10 different from the annual code changes? ICD-10 is different from the annual code changes because it is a full replacement of ICD-9. The ICD-10 code set is more robust and descriptive than ICD-9 and contains up to seven alpha and numeric characters, as opposed to ICD-9 codes that contain up to five characters. ICD-10 allows for greater specificity and granularity.
  • 7. What happens if a covered entity doesn’t switch to ICD-10? Claims that do not contain ICD-10 diagnosis and inpatient procedure codes for services provided on or after the implementation date will not be processed. They will be considered non-HIPAA compliant.
  • 8. Will there be a grace period for providers to submit ICD-9 and/or ICD-10 codes? No. Legislation mandates the use of the ICD-10 code set. Unless Congress acts to approve an extension, CMS has set the compliance date for ICD-10 as Oct. 1, 2015.
  • 9. Why is the ICD-10 transition necessary? Legislation passed in 2009 mandates the use of the ICD-10 code set.


  • 1. What is capitation?

    Health care providers who have entered into a capitated agreement with Humana will receive a check per member/per month (PMPM) regardless of whether they see the member. Capitation may be paid to primary care providers (PCPs) and specialist groups with which the PCPs are contracted, such as dermatology, cardiology, etc.

  • 2. What are the capitation rates?

    Capitation amounts can be a flat rate calculated by Humana or a percentage of premium determined by CMS. Capitation rates are defined in health care providers’ contracts with Humana.

  • 3. How does Humana plan to manage capitation reconciliations with ICD-10?

    Humana does not expect an impact to capitation. Our capitation reconciliation will follow the normal process.

Diagnosis-related group (DRG)

  • 1. Will DRG groupers continue to be based on ICD-9 codes?

    No. CMS defines DRG codes. DRGs will be based on ICD-10 codes when ICD-10 is implemented.

  • 2. What DRG grouper logic is Humana using, and are the DRGs being optimized for ICD-10?

    Humana currently uses version 32 DRG grouper logic. We will continue to transition to the latest groupers as they are released by CMS.


  • 1. What is an encounter?

    An encounter is a unique type of claim. Encounter data are used to determine a member’s health status. Encounter data are submitted by physicians or physician groups that have a capitated agreement with Humana or are delegated for claims.

  • 2. Why are encounters critical?

    Although encounters do not generate payments to the rendering provider, encounter information is used for Healthcare Effectiveness Data and Information Set (HEDIS®) reporting. Also, encounters are a primary driver for risk-adjustment scoring.

  • 3. How do encounters impact the member and physician?

    If diagnosis codes are fully documented on a Medicare Advantage member’s encounter, then Humana can accurately identify a member’s diagnosis and enroll the member in clinical programs that will assist in managing his/her more serious conditions.

  • 4. Which diagnosis codes need to be included on the claim/encounter?

    Encounters/claims must contain all diagnosis codes for which the member was treated and/or monitored during his or her visit and which are appropriately documented in the medical record. This includes chronic conditions and/or comorbidities that may affect the medical decision-making for the patient during that encounter.

Humana’s readiness

  • 1. Will Humana accept ICD-10 codes before the implementation date?

    No. The ICD-10 code set is not valid until Oct. 1, 2015, and ICD-10 codes will not be accepted before the implementation date. Claims submitted after the implementation date that contain dates of service before the implementation date must use ICD-9 codes.

  • 2. Does Humana plan to be ready to process ICD-10 codes submitted on claims forms by the compliance date?


  • 3. Does Humana provide regular and ongoing communication to health care providers regarding ICD-10 efforts and status?

    Yes. Humana’s ICD-10 program team has a communication plan and schedule for keeping Humana’s testing partners, trading partners, health care providers and internal departments informed. has an ICD-10 site located on the medical provider portal. Humana’s YourPractice, Humana’s online provider newsletter, also contains ICD-10 information.

    You may visit the ICD-10 site at

    You may view Humana’s YourPractice publication at

  • 4. When will Humana’s ICD-10 upgrades be complete?

    Humana’s internal systems have been remediated and are ICD-10 ready. However, Humana’s system remediation changes will not be visible to health care providers. Humana’s ICD-10 program began in 2009, and Humana will continue external testing through the compliance date.

  • 5. How will Humana handle denials and appeals with ICD-10?

    Denials and appeals will follow the existing process.

  • 6. Is Humana collaborating with the health care community to transition to ICD-10?

    Yes. Humana began conducting external end-to-end testing with a select group of early adopters (facilities) in 2012. We began testing with a select group of physicians and claim delegates in early 2015. Humana’s testing with facilities and physician groups is currently at capacity, and we are not able to accept new testing partners.

ICD-9 to ICD-10 processing plan

  • 1. Has Humana defined the process for readmission claims within 30 days?

    Yes. Humana will follow the current claims submission process.

  • 2. What is Humana's plan for ICD-10 acceptance?

    Humana will support both ICD-9 and ICD-10 coding formats for a period of time after the compliance date. However, Humana will accept only correctly formatted claims, both electronic and paper, which contain ICD-10 codes for service dates and discharge dates on or after the compliance date. Humana will accept ICD-9 codes for service dates or discharge dates prior to the compliance date for the contracted run-out period or timely filing requirements.

  • 3. Does Humana anticipate claims-processing issues related to ICD-10?

    No. Humana has invested in remediation of systems and processes to support ICD-10 requirements. Our advance testing will help mitigate claims-processing issues.

  • 4. Can one claim be submitted for services that span the CMS compliance date of Oct. 1, 2015?

    For outpatient services only: No. Per CMS, Humana will require claims with dates of service that extend past the compliance date to be split into separate claims. This means that all services that occur before the compliance date should use ICD-9 codes and should be billed separately from services with dates of service on or after the compliance date, which should contain only ICD-10 codes.

    For inpatient service only: Yes. The date of discharge will determine which ICD code set should be used. For inpatient services, if the date of discharge is on or after the compliance date, the claim should be submitted using only ICD-10 codes. If the date of discharge is before the compliance date, ICD-9 codes should be used.

    Humana will follow CMS or current state filing requirements. Here is a link to CMS guidance on claims that span the compliance date. Humana will follow this guidance:

  • 5. How will Humana handle authorization of services that occur on or after the ICD-10 compliance date?

    Humana began accepting authorizations and referrals with ICD-10 codes on July 1, 2015, and will continue to accept authorizations/referrals with ICD-9 codes for 12 months after the implementation date.

    If an authorization is requested on or before the compliance date and the date of service is on or after Oct. 1, 2015, providers may submit an ICD-10 code, though ICD-9-coded authorizations/ referrals will also be accepted.

    If the authorization is requested on or after the compliance date, Humana will accept and retain ICD-10 codes and will also allow ICD-9 submissions, just not on the same authorization or referral. Humana will not accept any ICD-9 authorization codes after Sept. 30, 2016.

  • 6. Will the appeal process for resubmission of ICD-9-based claims with ICD-10 codes change during the transition period?


  • 7. Will there be extensions given for timely filing during the ICD-10 transition time?

    No. Humana does not anticipate the use of timely filing extensions.

  • 8. Will reporting formats change?

    Yes. Reporting formats that include ICD-9 today will be remediated to reflect ICD-10 codes.

  • 9. Will your remediation plans vary by product or platform?

    No. ICD-10 will be applied through all products and platforms.

  • 10. If I submit or process a transaction with an ICD-9 code for a date of service after the compliance date, will I be HIPAA-compliant?

    No. The date of service determines the compliant code format to be used on a claim, regardless of the date the claim is filed or submitted.

    Health care providers must submit claims before the compliance date with ICD-9 codes when the services were performed prior to the compliance date. .

    Payers will process claims if received on or after the compliance date with ICD-9 codes when the services were performed prior to the compliance date. .

    This situation is HIPAA-compliant. .

  • 11. Will you accept 837 batches with both ICD-9 and ICD-10 claims spanning the conversion deadline?

    Yes. Humana will accept 837 batches containing both ICD-9 and ICD-10 claims as long as both codes are not contained on the same claim.

  • 12. What are the plans for restrictions on the acceptance of the unspecified codes for ICD-10?

    Humana will follow current CMS guidelines. Per CMS, each health care encounter should be coded to the level of certainty known for that encounter. Clinicians should report unspecified codes when such codes most accurately reflect what is known about the patient’s condition at the time of that particular encounter. It is inappropriate to select a specific code that is not supported by the medical record documentation.

  • 13. Are there Humana HIPAA companion guides that are ICD-10 compliant?

    Yes. The version 5010 companion guide can be located through the following link:

  • 14. Will claims that don’t meet specifications be rejected at point of receipt, or will a denial be issued?

    They will be rejected at point of receipt.

  • 15. Will the claim resubmission process change with ICD-10?

    No. Resubmission processes will continue to follow current guidelines.

  • 16. How will the transition from ICD-9 to ICD-10 work with eligibility transactions and subsequent episodes of care?

    All eligibility transactions using a diagnosis code must be compliant with ICD-10 upon the compliance date.

  • 17. Does Humana require/support interim billing?

    No. Humana does not support interim billing.

  • 18. What ICD-10 training will be provided to health care providers?

    Humana publishes current ICD-10 information and training opportunities at

    The health care community should visit the CMS website for the most current ICD-10 information:


  • 1. What are General Equivalence Mappings (GEMs)?

    General Equivalence Mappings (GEMs) are a CMS translation tool that can be used to convert large sets of data from ICD-9 to ICD-10. According to CMS, GEMs are useful in converting databases but are not a substitute for learning how to use ICD-10 codes. Mapping links the two code sets without considering the patient’s medical record information. Coding involves choosing the appropriate code based on the medical record documentation.

  • 2. Is Humana using CMS GEMs as part of its process?

    Yes. Humana is using CMS GEMs as a guideline to map ICD-9 codes to ICD-10 codes. However, based on clinical guidance and coding expertise, there may be instances when Humana finds additional codes appropriate, above and beyond the GEMS mappings. Humana always recognizes a GEMS-proposed mapping.

  • 3. Will Humana cross-walk incoming claims with ICD-9 codes to ICD-10?

    No. Humana will process claim transactions in their native format and will not cross-walk ICD-9 codes to ICD-10. Claims with improper diagnosis codes (based on date of service or date of discharge) will be rejected.

Medicaid risk adjustment

  • 1. What is Medicaid risk adjustment?

    Medicaid risk adjustment is a process used to calculate payments related to the treatment of select conditions known as “disease categories.” Reimbursement for services related to these conditions is weighted based on the relative health of a beneficiary.

  • 2. What should I know about Medicaid risk adjustment and ICD-10 coding?

    Medicaid plans vary by state, but the key to accurate Medicaid reimbursement is to code accurately and to the highest level of specificity to ensure the disease categories are triggered, if warranted.

Medical policy and medical necessity

  • 1. Will Humana update its medical and pharmacy coverage policies as a result of the more specific codes that will be available?

    Yes. Humana has reviewed and updated its medical policies to incorporate new ICD-10 terminology and expanded coding. Humana publishes medical policies on its provider website at Choose “For Providers” then select “Medical and pharmacy coverage policies” under the “Resources” heading. Humana has updated medical policies to reflect ICD-10 changes. The policies section of the website also includes Information on medical necessity requirements, coverage determinations and payment determinations.

Medicare Advantage hierarchical condition categories

  • 1. What is a hierarchical condition category (HCC)?

    HCCs represent categories of health conditions, both chronic and acute, that are used to project health care costs for Medicare Advantage members for current and future coverage periods. Diagnosis codes are mapped to HCCs for conditions such as diabetes, congestive heart failure, etc. Members may have multiple HCCs.

  • 2. When will CMS release HCCs for ICD-10?

    CMS posted a preliminary ICD-10-HCC crosswalk on Feb. 24, 2014. There are approximately 10,100 diagnosis codes that have been identified as appropriate for Medicare risk adjustment, and these are mapped to the various HCC models.

  • 3. How do HCCs contribute to a member’s risk score?

    Each HCC is assigned a decimal value that contributes to the member’s risk score.

Medicare Risk Adjustment

  • 1. What is risk adjustment?

    Risk adjustment is a process in which per-member reimbursements from CMS are adjusted to correspond with the member’s health status, which is based upon submitted diagnosis codes. When encounters are not submitted, Humana and CMS do not have complete member information. Risk adjustment was implemented to reimburse Medicare Advantage plans more accurately for predicted health cost expenditures for members by adjusting payments based on demographics (e.g., age and gender), as well as health status.

  • 2. How does risk adjustment impact physicians and members?

    Increased coding accuracy helps Humana identify members who may benefit from disease and medical management. Accurate health information is used to match health care needs to the appropriate level of care.

Outpatient vs. inpatient

  • 1. What is the deciding factor on when to use ICD-10 codes?

    For outpatient services, ICD-10 codes are required for dates of service on or after the compliance date. For inpatient services, ICD-10 codes are required on the date of discharge on or after the compliance date.

  • 2. Will ICD-10 replace Current Procedural Terminology (CPT®) or Healthcare Common Procedure Coding System (HCPCS) coding?

    No. CPT and HCPCS coding for outpatient procedures are not affected. ICD-10 procedure codes apply to hospital inpatient procedures only.

  • 3. Will there be special handling for patients who are in-house over the transition?

    Yes. Claims for patients in-house over the transition date should be submitted based on the discharge date, using the most recent CMS recommendations.

Provider readiness

  • 1. What key information should health care providers keep in mind as they develop their own ICD-10 implementation plans?

    Humana suggests that health care providers stay up to date on changes from CMS regarding ICD-10 implementation via the CMS website and the other resources listed below.

  • 2. Will clinicians need to learn thousands of new codes?

    Not necessarily. While ICD-10 provides a larger code set, most specialists typically use a narrow range of diagnosis codes. The American Academy of Professional Coders (AAPC) has published a crosswalk of the top 50 codes for 16 specialties here: This crosswalk does not replace ICD-10 coding training, and we strongly advise you seek recommended resources and look to your professional associations for training and guidance.

  • 3. Will Humana renegotiate provider contracts to replace ICD-9 codes with ICD-10?

    Yes. We currently have diagnosis-related groups (DRG) and ICD contract language in a small percentage of our contracts, and Humana will work with health care providers to update contracts where required. Contract changes will follow the normal process. If a health care provider’s contract has specific ICD or DRG language, he or she should contact the appropriate market representative to facilitate a contract revision. If you are unsure how to locate your market representative, please contact provider relations at 1-800-626-2741.

  • 4. How can health care providers find out if they are required to purchase additional hardware, software licenses and/or subscription fees to support ICD-10 changes or enhancements?

    Health care providers need to contact their software vendors for requirements.

  • 5. Do you have ICD-10-related information we can subscribe to or a point of contact for more information?

    We do not have a subscription list, but we do post ICD-10 information at Additionally, if you have an ICD-10 question not answered here, you may send it to


  • 1. Do you anticipate changes in policies or delays in payments after the switch to ICD-10?

    Humana does not expect a delay in payment or policy changes regarding the way a claim is adjudicated under ICD-10. Prompt payment can occur if claims are properly coded based on the latest CMS guidelines. Claims may be reviewed or denied if an ICD-10 code is not consistent with an applicable Humana or CMS policy.

Other resources

IMPORTANT: The information contained on this website is designed to provide a general overview of what can be expected with the transition from the International Statistical Classification of Diseases and Related Health Problems, Ninth Revision, (ICD-9) to ICD-10 as it impacts Humana’s business. The information provided is not intended to address all of the Centers for Medicare & Medicaid Services (CMS) requirements and implications mandating the use of ICD-10 and should not be used as legal advice for implementation activities. We encourage you to seek any professional advice you may need, including legal counsel, regarding how the new requirements will affect your specific practice. Humana provides the information on this site for general informational purposes only.