Relationship of Diagnosis Codes and Date of Service

Diagnosis codes must be reported based on the date of service (including, when applicable, the date of discharge) on the claim and not the date the claim is prepared or received. A/B MACs (A), (B), (HHH), and DME MACs are required to edit claims on this basis, including providing for annual updates each October.

Shared systems must maintain date parameters for diagnosis editing. Use of actual effective and end dates is required when new diagnosis codes are issued or current codes become obsolete with the annual updates.


The Health Insurance Portability and Accountability Act (HIPAA) requires that medical code sets must be date-of-service compliant. Since ICD diagnosis codes are a medical code set, effective for dates of service on and after October 1, 2004, CMS does not provide any grace period for providers to use in billing discontinued diagnosis codes on Medicare claims. The updated codes are published in the Federal Register each year as part of the Proposed Changes to the Hospital Inpatient Prospective Payment Systems in table 6 and effective each October 1.

All MACs will return claims containing a discontinued diagnosis code as unprocessable. For dates of service beginning October 1, 2004, physicians, practitioners, and suppliers must use the current and valid diagnosis code that is then in effect for the date of service. After the updated codes are published in the Federal Register, CMS places the new, revised and discontinued codes on the ICD-9 or ICD-10 Web site as applicable.

http://www.cms.gov/Medicare/Coding/ICD9ProviderDiagnosticCodes/codes.html
or http://www.cms.gov/Medicare/Coding/ICD10/index.html.

The CMS sends the updated codes to All MACs on an annual basis via a recurring update notification instruction. This is normally released to MACs each June, and contains the new, revised, and discontinued diagnosis codes which are effective for dates of service on and after October 1st.