Excludes1 pair

K26- vs K63.3

K26 and K63.3 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 K63.3
duodenal ulcer (K26.-)
K26

Duodenal ulcer

Not billable
Chapter 11
Diseases of the digestive system
Section
K20-K31
Use when the record says
  • erosion (acute) of duodenum
  • duodenum ulcer (peptic)
  • postpyloric ulcer (peptic)
K63.3

Ulcer of intestine

Billable
Chapter 11
Diseases of the digestive system
Section
K55-K64
Use when the record says
  • Primary ulcer of small intestine
Indexed under
  • Stercoraceous, stercoral ulcer
  • Erosion › intestine
  • Ulcer, ulcerated, ulcerating, ulceration, ulcerative › intestine, intestinal
  • Ulcer, ulcerated, ulcerating, ulceration, ulcerative › primary of intestine
  • Ulcer, ulcerated, ulcerating, ulceration, ulcerative › rectosigmoid

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