FY2027
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Excludes1 pair

Y66 vs Z66

Y66 and Z66 are not coded together. ICD-10-CM declares them mutually exclusive with an Excludes1 note — the two conditions are not expected to occur together, so exactly one of them is normally correct for a given encounter. The Official Guidelines carve out one exception: if the two conditions are clearly unrelated to each other, both may be reported.

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 (DNR)

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