H81 vs R42
H81 and R42 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 H81
vertigo NOS (R42)
H81
Disorders of vestibular function
Not billable
- Chapter 8
- Diseases of the ear and mastoid process
- Section
- H80-H83
R42
Dizziness and giddiness
Billable
- Chapter 18
- Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
- Section
- R40-R46
Use when the record says
- Light-headedness
- Vertigo NOS
Indexed under
- Dizziness
- Dysequilibrium
- Giddiness
- Swimming in the head
- Vertigo
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