K30 vs R12
K30 and R12 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 K30
heartburn (R12)
K30
Functional dyspepsia
Billable
- Chapter 11
- Diseases of the digestive system
- Section
- K20-K31
Use when the record says
- Indigestion
Indexed under
- Acidity, gastric (high)
- Apepsia
- Indigestion (acid) (bilious) (functional)
- Acid › peptic disease
- Acid › stomach
R12
Heartburn
Billable
- Chapter 18
- Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
- Section
- R10-R19
Indexed under
- Brash (water)
- Heartburn
- Pyrosis
- Waterbrash
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