ICD-10 Overview

Important Update

Starting January 1, 2024, California Health & Wellness Plan will no longer serve Medi-Cal members. The information and resources provided on this webpage are applicable to services rendered on or before December 31, 2023.

If you are a provider in Amador, Calaveras, Imperial, Inyo, Mono, or Tuolumne counties, who is part of the Health Net provider network starting January 1, 2024, please visit Health Net for services rendered on or after January 1, 2024.

The International Classification of Diseases (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 ICD-9 is 30 years old, has outdated terms, and is inconsistent with advancements in medical technology and knowledge.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 three to seven alphanumeric digits instead of the three to five 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.

California Health & Wellness will be ICD-10 compliant by 10/1/2015. California Health & Wellness 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 if the date of discharge / date of service is prior to the 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 this claims processing document (SE1408 (PDF))
  • 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

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 EDIBA@centene.com for further instructions.

Providers or clearinghouses who are interested in testing must be direct electronic claim submitters (837 X12 claims).

End-to-End Testing

A spectrum of claims test cases were tested internally among IT systems. Based on the successful passing of claims test cases during internal end-to-end testing, external end-to-end testing with providers was initiated.

The objective of external end-to-end testing was to demonstrate the ability to process ICD-10 claims from end-to-end successfully. Providers were instructed to submit electronic claim files (837 files), which were sent through claims processing systems and an electronic remittance file (835 files or suitable replacement) was generated. The results of testing reaffirmed that the claims processing systems were ICD-10 capable and ready.

Testing was coordinated by our parent company, Centene Corporation. Forty-six provider groups and clearinghouses participated and 1,648 claims were processed.

Another end-to-end testing exercise will not be conducted due to the success of the completed testing initiative. While it would be advantageous to test with all providers, clearinghouses, and vendors, California Health & Wellness believes the incremental benefits of conducting further testing are outweighed by the costs of execution. To successfully prepare for submitting claims with ICD-10 codes, entities should conduct “claims format” testing through Centene’s Ramp Manager application, which is self-service and available for us from now until the ICD-10 transition. This testing will help to ensure that claims are not rejected upon submission and are billed properly.