Follow Taxonomy Code Attestation Requirements to Avoid Medicaid Claim Rejections or Denials

Nov. 11, 2025

In July, we alerted you of claims processing changes and billing reminders for Blue Cross Community Health PlansSM. To align with Illinois Medicaid billing requirements, it’s important that you submit claims with appropriate taxonomy codes to identify the provider type and specialty. This applies to each billing, servicing, rendering or attending provider defined on the claim. Failure to report the appropriate taxonomy code will result in claim rejections or denials, as of Aug. 1, 2025. Additional details and reminders are below.

Taxonomy code attestation: Refer to the Illinois Association of Medicaid Health Plans Comprehensive Billing Manual and the National Uniform Claim Committee Health Care Provider Taxonomy Code Set to confirm you’re using the appropriate taxonomy code based on the provider type and specialty or category of service that matches your registration within the Illinois Medicaid Program Advanced Cloud Technology system.

Waiver providers: All Medicaid waiver providers will be required to submit the appropriate taxonomy code for the service rendered as defined by the IAMHP Comprehensive Billing Manual.

  • For electronic claims (837 transactions), report the appropriate taxonomy code in Loop 2000A*PRV03.
  • For paper claims (1500 Claim Form), report the taxonomy code in Box 24J with the ZZ qualifier in Box 24I.

Tips for resolving attestation denials or rejections:

  1. Verify all reported providers have active enrollment with the state of Illinois in the IMPACT system for the dates of service on the claim.
  2. Verify required providers are reported on the claim. Refer to the IAMHP Comprehensive Billing Manual for requirements by provider type.
  3. Verify the taxonomy codes for each provider reported on the claim are appropriate for the registered provider type. Consult the provider’s primary taxonomy code listed in the National Plan and Provider Enumeration System National Provider Identifier Registry and review the guidance in the IAMHP Comprehensive Billing Manual or NUCC Health Care Provider Taxonomy Code Set for the appropriate taxonomy code.
  4. Ensure ordering, referring or prescribing provider reporting requirements have been met on the claim. Refer to Appendix G of the IAMHP Comprehensive Billing Manual for requirements.

If all steps have been completed and no discrepancy is identified, contact Provider Relations for further assistance.