Y66 vs Z66
Y66 and Z66 can never be reported together. ICD-10-CM declares them mutually exclusive with an Excludes1 note, meaning the two conditions cannot occur in the same patient — so exactly one of them is correct for any given encounter.
The official note, declared on Y66
DNR status (Z66)
Y66
Nonadministration of surgical and medical care
Billable
- Chapter 20
- External causes of morbidity
- Section
- Y62-Y69
Use when the record says
- Premature cessation of surgical and medical care
Z66
Do not resuscitate
Billable
- Chapter 21
- Factors influencing health status and contact with health services
- Section
- Z66
Use when the record says
- DNR status
Indexed under
- DNR (do not resuscitate)
- Status › do not resuscitate (post)
These two codes sit in different chapters of the Tabular List, which is usually the clearest signal that they describe different underlying processes rather than different degrees of the same one.
Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027