FY2027
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Excludes1 pair

K65.2 vs K65.9

K65.2 and K65.9 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 K65.2
bacterial peritonitis NOS (K65.9)
K65.2

Spontaneous bacterial peritonitis

Billable
Chapter 11
Diseases of the digestive system
Section
K65-K6A
Indexed under
  • Peritonitis › spontaneous bacterial
K65.9

Peritonitis, unspecified

BillableUnspecified
Chapter 11
Diseases of the digestive system
Section
K65-K6A
Use when the record says
  • Bacterial peritonitis NOS
Indexed under
  • Peritonitis (adhesive) (bacterial) (fibrinous) (hemorrhagic) (idiopathic) (localized) (perforative) (primary) (with adhesions) (with effusion)
  • Fistula › peritoneum
  • Hemoperitoneum › infectional

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