The bridge from ICD-10-CM

Hook

If you code in ICD-10-CM today, you already know what a diagnosis code is for. ICD-11 asks you to think about the same job in a different way.

Where icd-10-cm comes from

ICD-10-CM is the United States' clinical modification of ICD-10. CDC's National Center for Health Statistics is responsible for it. ICD-10-PCS, the procedure system for inpatient care, was developed by CMS, and ICD-11 doesn't replace it.

How icd-10-cm carries detail

In ICD-10-CM, detail is built into the code. Codes run from three to seven characters, with a decimal after the third. When a new combination of clinical facts matters, a code for it has to exist. Side, severity and cause are often part of the code itself.

How icd-11 carries detail

ICD-11 keeps a smaller number of core categories, more than 17,000 of them, and adds detail with extension codes, clustered with the stem code. Side, severity and cause become extensions you add. That means one diagnosis can need several codes, so the number of codes per diagnosis can go up, even though the classification is smaller.

Side by side

Same clinical statement, two approaches. In ICD-10-CM, the detail you can express is the detail the code set has built in. In ICD-11, you assemble the detail: the condition, then the side, then the cause. The skill that carries over is documentation. The more specific the note, the better either system works.

What hasn't changed

What hasn't changed is this. US claims still run on ICD-10-CM, and ICD-10-CM is still the HIPAA code set. As of 13 October 2026, we found no published US implementation date or proposed rule. So you aren't coding claims in ICD-11 today. You're building understanding.

What to watch

Where would you hear first? NCVHS meetings, the NCHS ICD pages, CMS rulemaking and the Federal Register. A proposed rule is what would start the planning clock.

Recap

Same job, different build. ICD-10-CM builds detail into the code; ICD-11 assembles it. Documentation specificity carries over. And watch the Federal Register.