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. Medicare contractors are required to be able to edit claims on this basis, including providing for annual updates each October. The effective date for this requirement is:
• Claims to DMERCs – April 1, 2003;
• Claims to carriers – October 1, 2002; and
• Claims to intermediaries – October 1, 1983.
Shared systems must establish 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 ICD-9-CM updates. During implementation, for codes already established on the shared system files, the effective date could be defaulted to January 1, 1990. Any codes on claims to carriers and DMERCs currently identified as no longer effective upon implementation could be considered to have an end date of December 31, 2001. Thereafter, any additions or terminations must have the actual effective and end date.
The Health Insurance Portability and Accountability Act (HIPAA) requires that medical code sets must be date-of-service compliant. Since ICD-9-CM diagnosis codes are a medical code set, effective for dates of service on and after October 1, 2004, CMS will no longer provide a 90-day grace period for providers to use in billing discontinued ICD-9-CM diagnosis codes on Medicare claims. The updated ICD-9-CM codes are published in the Federal Register in April/May of each year as part of the Proposed Changes to the Hospital Inpatient Prospective Payment Systems in table 6 and effective each October 1.
Carriers and DMERCs must eliminate the ICD-9-CM diagnosis grace period from their system effective with the October 1, 2004 update. Carriers and DMERCs will no longer accept discontinued diagnosis codes for dates of service October 1 through December 31 of the current year. Claims containing a discontinued ICD-9-CM diagnosis code will be returned 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. After the ICD-9-CM codes are published in the Federal Register, CMS places the new, revised and discontinued codes on the following Web site: http://www.cms.hhs.gov/medlearn/icd9code.asp
 
The CMS sends the updated ICD-9-CM addendum to contractors on an annual basis via a recurring update notification instruction. The addendum is normally released to contractors each June. The addendum contains the new, revised, and discontinued diagnosis codes which are effective for dates of service on and after October 1st.