FY2027
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Excludes1 pair

D22- vs I78.1

D22 and I78.1 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 I78.1
nevus NOS (D22.-)
D22

Melanocytic nevi

Not billable
Chapter 2
Neoplasms
Section
D10-D36
Use when the record says
  • atypical nevus
  • blue hairy pigmented nevus
  • nevus NOS
I78.1

Nevus, non-neoplastic

Billable
Chapter 9
Diseases of the circulatory system
Section
I70-I79
Use when the record says
  • Araneus nevus
  • Senile nevus
  • Spider nevus
  • Stellar nevus
Indexed under
  • Telangiectasia, telangiectasis (verrucous)
  • Angioma › capillary
  • Angioma › senile
  • Angioma › spider
  • Angioma › stellate

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