MCMCB Pro
K91.850

K91.850Pouchitis

Billable / specific codeICD-10-CM

K91.850 is a billable, specific ICD-10-CM code for pouchitis. It is valid for submission on a claim.

Inclusion terms

Alternative wordings a physician may use in the chart for this same code.

  • Inflammation of internal ileoanal pouch

Risk adjustment

K91.850 risk-adjusts. Under the CMS-HCC V28 model it maps to this category:

  • HCC 463 Artificial Openings for Feeding or Elimination0.673 RAF

Coefficient shown for the Community Non-dual Aged segment. A higher HCC in the same hierarchy will suppress this one, so capturing it does not always add score.

Medicare coverage

K91.850 is named in 6 Medicare coverage policies 6 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

  • A55937Billing and Coding: Diagnostic Colonoscopy
  • A56421Billing and Coding: CT of the Abdomen and Pelvis
  • A56456Billing and Coding: Colonoscopy/Sigmoidoscopy/Proctosigmoidoscopy
  • A56632Billing and Coding: Colonoscopy/Sigmoidoscopy/Proctosigmoidoscopy

How K91.850 is indexed

Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to K91.850.

  • Pouchitis
  • Inflammation, inflamed, inflammatoryileoanal pouch(internal)
  • Inflammation, inflamed, inflammatoryintestinal pouch

Related codes at this level

Codes that share K91.85. If K91.850 is not quite right, the correct code is usually one of these.

Questions about K91.850

Is K91.850 a billable ICD-10-CM code?
Yes. K91.850 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does K91.850 sit in the tabular list?
Diseases of the digestive system (K00-K95), in the block Other diseases of the digestive system (K90-K95).
ICD-10-CMFY2026-Apr· effective April 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release — see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.