This guide outlines what U.S. medical practices should know about ICD-11. As of 2026, ICD-10-CM remains the mandatory billing standard in the United States. No U.S. mandate date for ICD-11 adoption has been announced by HHS or CMS.
What Is ICD-11 and Why Does It Matter?
ICD-11 (International Classification of Diseases, 11th Revision) is the WHO's most current disease classification system. Unlike the ICD-10 transition, ICD-11 introduces entirely new structural concepts, a dramatically expanded code set (55,000+ codes vs. 14,000 in ICD-10-CM), and a digital-first architecture.
Key Differences from ICD-10
- Code Structure: Up to 6 characters (vs. ICD-10's 7) with different alphanumeric patterns
- Code Volume: 55,000+ entities vs. 14,400 in ICD-10-CM
- New Chapter: Dedicated chapters for Sexual Health and Traditional Medicine
- Digital Integration: Built for electronic health records and AI-assisted coding
- Extension Codes: Post-coordination system replaces combination codes
Timeline Note: The U.S. implementation timeline is still under CMS
review. However, most experts recommend beginning preparation now, particularly staff training and EHR
assessments.
Your ICD-11 Preparation Checklist
- Assess your EHR vendor's ICD-11 roadmap and implementation timeline
- Begin staff education on structural differences from ICD-10
- Identify your highest-volume diagnosis codes and map them to ICD-11 equivalents
- Review payer readiness — most major payers have not yet announced ICD-11 acceptance dates
- Download our free ICD-11 Preparation Guide for a full 45-step checklist