ICD-10 frequently asked questions


  • 1. What is ICD-10, and who does it affect? ICD-10 stands for the International Classification of Diseases, 10th Edition. ICD is the international standard for diagnostic classifications. The previous 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 was the primary purpose of the switch to ICD-10? The primary purpose of the ICD-10 implementation was 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. ICD-10 coding also enables the United States to exchange information across international borders.
  • 3. How was the transition to ICD-10 different from the annual code changes? ICD-10 is different from the annual code changes because it was 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.


  • 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.

Diagnosis-related group (DRG)

  • 1. Are DRG groupers still based on ICD-9 codes?

    No. DRGs are now based on ICD-10 codes.

  • 2. What DRG grouper logic is Humana using?

    Humana plans to implement version 34 DRG grouper logic on Oct. 1, 2016. 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.

ICD-9 to ICD-10 processing plan

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

    Yes. Humana follows 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 accepts 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 accepts 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. 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 requires 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 determines 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 follows CMS or current state filing requirements. Here is a link to CMS guidance on claims that span the compliance date. Humana follows this guidance:

  • 4. How does 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 continued to accept authorizations/referrals with ICD-9 codes for 12 months after the implementation date.

    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.

  • 5. Have reporting formats changed?

    Yes. Reporting formats that included ICD-9 have been remediated to reflect ICD-10 codes.

  • 6. 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. .

  • 7. Are there restrictions on the acceptance of the unspecified codes for ICD-10?

    Humana follows 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 only 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.

  • 8. 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.

  • 9. Did the claim resubmission process change with ICD-10?

    No. Resubmission processes will continue to follow current guidelines.

  • 10. Does Humana require/support interim billing?

    No. Humana does not support interim billing.

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

    Humana provides recorded ICD-10 training sessions at

    This CMS website provides 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. Did Humana update its medical and pharmacy coverage policies as a result of the more specific ICD-10 codes?

    Yes. Humana 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. 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. 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 Oct. 1, 2015. For inpatient services, ICD-10 codes are required on the date of discharge on or after Oct. 1, 2015.

  • 2. Did 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.

Other resources

IMPORTANT: The information contained on this website is designed to provide a general overview of what 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.