E16.4 vs K29
E16.4 and K29 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 K29
Zollinger-Ellison syndrome (E16.4)
E16.4
Increased secretion of gastrin
Billable
- Chapter 4
- Endocrine, nutritional and metabolic diseases
- Section
- E15-E16
Use when the record says
- Hypergastrinemia
- Hyperplasia of pancreatic endocrine cells with gastrin excess
- Zollinger-Ellison syndrome
Indexed under
- Ellison-Zollinger syndrome
- Hypergastrinemia
- Zollinger-Ellison syndrome
- Abnormal, abnormality, abnormalities › gastrin secretion
- Hypersecretion › gastrin
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