ICD-10-CM 2027
ICD-10 code for rectosigmoiditis
From the official ICD-10-CM alphabetic index entry “Rectosigmoiditis”. Page updated September 29, 2026.
About coding rectosigmoiditis
The ICD-10-CM code for rectosigmoiditis is K63.89 (Other specified diseases of intestine). The official index lists 7 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on K63.89.
Within K63.8, choose K63.89 (Other specified diseases of intestine) only when documentation doesn't support a more specific option: Dieulafoy lesion of intestine (K63.81) and intestinal microbial overgrowth (K63.82).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 393 (Other Digestive System Diagnoses with MCC, relative weight 1.5881), DRG 394 (Other Digestive System Diagnoses with CC, relative weight 0.9228) and DRG 395 (Other Digestive System Diagnoses without CC/MCC, relative weight 0.6382), in MDC 06 (Diseases and Disorders of the Digestive System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific rectosigmoiditis codes (official index)
- ulcerative (chronic) K51.30 — Ulcerative (chronic) rectosigmoiditis without complications
- with
- complication K51.319 — Ulcerative (chronic) rectosigmoiditis with unspecified complications
- abscess K51.314 — Ulcerative (chronic) rectosigmoiditis with abscess
- fistula K51.313 — Ulcerative (chronic) rectosigmoiditis with fistula
- obstruction K51.312 — Ulcerative (chronic) rectosigmoiditis with intestinal obstruction
- rectal bleeding K51.311 — Ulcerative (chronic) rectosigmoiditis with rectal bleeding
- specified NEC K51.318 — Ulcerative (chronic) rectosigmoiditis with other complication
Common questions about rectosigmoiditis ICD-10 codes
What is the ICD-10 code for rectosigmoiditis?
- K63.89 — Other specified diseases of intestine. More specific codes apply when the documentation supports them: K51.30, K51.319, K51.314, K51.313 and others below.
What is the ICD-10 code for ulcerative rectosigmoiditis?
- K51.30 — Ulcerative (chronic) rectosigmoiditis without complications.
Is K63.89 billable?
- Yes. K63.89 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can K63.89 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict K63.89 as a principal diagnosis.
Is K63.89 a CC or MCC?
- No. K63.89 is neither a CC nor an MCC under MS-DRG v44.0.