Skip to Main Content

ICD-10 Overview


ICD is a medical coding system created by the World Health Organization (WHO) and is used by payers and providers to identify diagnoses and procedures. ICD-9 is the current system used in the United States and was widely adopted in the world in 1978. Today, there are many limitations to continuing to use ICD-9 codes. Over 130 countries have transitioned to ICD-10 diagnosis and procedure coding, and the United States is set to transition to ICD-10 on 10/1/2015.

The transition to ICD-10 is occurring because ICD-9 produces limited data about patients' medical conditions and hospital inpatient procedures. ICD-9 is 30 years old, has outdated terms, and is inconsistent with advancements in medical technology and knowledge. Also, the structure of ICD-9 limits the number of new codes that can be created, and many ICD-9 categories are full. For example, new cardiac disease codes may be assigned to the chapter for diseases of the eye because of lack of available codes.

ICD-10-CM/PCS (International Classification of Diseases, 10th Edition, Clinical Modification/Procedure Coding System) consists of two parts:

  1. ICD-10-CM for diagnosis coding
  2. ICD-10-PCS for inpatient procedure coding

ICD-10-CM is for use in all U.S. health care settings. Diagnosis coding under ICD-10-CM uses 3 to 7 alphanumeric digits instead of the 3 to 5 alphanumeric digits used with ICD-9-CM, but the format of the code sets is similar. ICD-10-PCS is for use in U.S. inpatient hospital settings only. ICD-10-PCS uses 7 alphanumeric digits instead of the 3 or 4 numeric digits used under ICD-9-CM procedure coding. Coding under ICD-10-PCS is much more specific and substantially different from ICD-9-CM procedure coding.

Absolute Total Care will be ICD-10 compliant by 10/1/2015. Absolute Total Care will be able to process (send/receive) transactions and perform internal functions using ICD-10 diagnosis and procedure codes. Providers must submit claims with codes that align with CMS and state guidelines:

Claims Processing

The following information applies to paper, web, and standard electronic (837 X12) claims.

  • Claims may not contain a combination of ICD-9 and ICD-10 codes. 
  • Claims must be submitted with ICD-10 codes if the date of discharge / date of service is on or after the ICD-10 compliance date of 10/1/2015.
  • Claims must not be submitted with ICD-10 codes prior to compliance date of 10/1/2015.
  • For some claims which span the ICD-10 compliance date, the admit date on the claim can be prior to the ICD-10 compliance date and the claim can still contain ICD-10 codes. For other claims which span the ICD-10 compliance date, a splitting of the claim into two separate claims is necessary. CMS has outlined guidance on which claims will need to be split in these claims processing documents (SE1325 and MM7492).
  • CMS uses the “bill type” on an institutional claim for determining whether the claim should be split. In general, inpatient claims can have dates of service which span the compliance date and contain ICD-10 codes. Outpatient and professional claims cannot have dates of service which span the compliance date and have ICD-10 codes. For outpatient and professional claims, providers must split claims into two separate claims (one claim with a date of discharge on 9/30/15 and another claim with an admit date of 10/1/15).
  • Interim bills for long hospital stays (TOB: 112, 113, 114) are expected to follow the same rules as other claims. If a provider submits a replacement claim (TOB: 117) to cover all interim stays, it is expected that the provider must re-code all diagnoses / procedures to ICD-10 since the replacement claim will have a discharge / through date post-compliance.
  • All first-time claims and adjustments for pre-10/1/2015 service dates must include ICD-9 codes, even if claims are submitted post-10/1/2015. Claims with pre-10/1/2015 service dates can be submitted with ICD-9 codes for as long as contracts and provider manuals specify.
  • Reiteration: Claim submission date does not determine whether ICD-9/10 codes should be used. All ICD-9/10 claims submission rules outlined by CMS are based on patient discharge date, or date of service for outpatient/professional services.

Claims will be reimbursed according to state reimbursement guidelines. Claims will be adjudicated natively in ICD-9 for dates of service prior to 10/1/2015 and natively in ICD-10 for dates of service on and after 10/1/2015, consistent with CMS requirements.

Authorization Processing

ICD-10 diagnosis codes will be accepted on prior authorization requests submitted 7/1/15 or later for services with a start date on or after the ICD-10 compliance date. ICD-9 codes will no longer be accepted on prior authorization requests submitted on the ICD-10 compliance date or later except in the case of retro authorizations for services with a start date on or before 9/30/15. ICD-9 procedure codes are not used on authorizations and ICD-10 procedure codes will not be used on authorizations.

ICD-10 Implementation and Testing Approach

Our ICD-10 implementation approach aligns with CMS guidance and recommended timeframes.

Transactional-Level Testing

An ICD-10 assessment was completed in 2011-2012 and HIPAA compliance testing with providers, clearinghouses, vendors and state agencies began on July 2013. Transactional-level testing is available today to any provider interested in participating and will continue to be available through the ICD-10 compliance date. As part of this testing effort, providers who register in Ramp Manager (application used for all testing efforts) and submit 837 X12 test claims will receive TA1, 999, 277CA, and 271 eligibility responses.

Providers or clearinghouses who are interested in transactional-level testing can contact the EDI service desk at 1-800-225-2573, ext. 25525 or for further instructions. Providers or clearinghouses who are interested in testing must be direct electronic claim submitters (837 X12 claims).

End-to-End Testing

End-to-end testing will broaden the focus of transactional-level testing and will encompass the return of remittance advices (RAs) / explanation of payments (EOPs). Providers who conduct end-to-end testing will receive the outputs from transactional-level testing in addition to an 835 X12 Remittance Advice file.

Providers or clearinghouses who are interested in conducting end-to-end testing should reach out to the health plan for further details. If contacts within the health plan are unavailable, interested providers can contact

End-to-end testing will only be conducted with a limited number of providers and will occur in Q1-Q2 2015. Providers and clearinghouses who are confirmed as test partners will be permitted to submit up to 50 ICD-10 coded test claims in an electronic 837 X12 format. The Ramp Manager application (application used for all testing efforts) will be used as a mechanism for receiving electronic test claims and distributing electronic remittance advices. Providers who normally submit claims via clearinghouses will be asked to work with their clearinghouse on test claim submissions.