O99 vs Z72.0
O99 and Z72.0 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.
Other maternal diseases classifiable elsewhere but complicating pregnancy, childbirth and the puerperium
- Chapter 15
- Pregnancy, childbirth and the puerperium
- Section
- O94-O9A
- conditions which complicate the pregnant state, are aggravated by the pregnancy or are a main reason for obstetric care
Tobacco use
- Chapter 21
- Factors influencing health status and contact with health services
- Section
- Z69-Z76
- Tobacco use NOS
- Tobacco › harmful use (nicotine)
- Tobacco › use (nicotine)
- Use › tobacco (of)
- Problem › life-style › tobacco use (with) (related to)
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