K51.31 – Ulcerative (chronic) rectosigmoiditis with complications

ICD-10-CM 2027 diagnosis code · Noninfective enteritis and colitis

Non-billable header

ICD-10-CM code K51.31
Code
K51.31 (claims format: K5131)
Description
Ulcerative (chronic) rectosigmoiditis with complications
Billable
No – use a more specific code below
Valid for
Dates of service October 1, 2026 – September 30, 2027 (FY2027)
Chapter
11. Diseases of the digestive system (K00-K95)
Block
K50-K52 Noninfective enteritis and colitis
Parent codes
K51 › K51.3

Billable codes under K51.31

K51.31 is a header code and cannot be used on claims. Choose the most specific code:

Notes inherited from parent codes

Instructional notes at a category or block level apply to every code below it.

K51 – Ulcerative colitis

Excludes1 (not coded here):
  • Crohn's disease [regional enteritis] (K50.-)
Use additional code:
  • code to identify any associated fistulas, if applicable:
  • anal fistula (K60.3-)
  • anorectal fistula (K60.5-)
  • rectal fistula (K60.4-)
  • code to identify manifestations, such as:
  • pyoderma gangrenosum (L88)

Block K50-K52

Includes:
  • noninfective inflammatory bowel disease
Excludes1 (not coded here):
  • irritable bowel syndrome (K58.-)
  • megacolon (K59.3-)

Related codes in K51.3

Frequently asked questions

What is ICD-10 code K51.31?

K51.31 is the ICD-10-CM code for ulcerative (chronic) rectosigmoiditis with complications, in the block K50-K52 (Noninfective enteritis and colitis).

Is K51.31 a billable code?

No. K51.31 is a header code with more specific child codes; report one of the billable codes listed above.

What category does K51.31 belong to?

It belongs to category K51 – Ulcerative colitis.

Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.