Alphabetic Index FY2027

K61.1

Rectal abscess

FY2027Chapter 11: Diseases of the digestive system/K55–K64 Other diseases of intestines

BillableComplete code, valid to report
Care settingsHome Health Primary · MMTA - Gastrointestinal tract and Genitourinary systemHospital CC

K61.1 (also written K611) is a billable ICD-10-CM diagnosis code for rectal abscess. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 7 codes in category K61 (Abscess of anal and rectal regions). The Alphabetic Index lists it under 6 entries. Its coding notes include 1 Excludes1 entry and 8 Excludes2 entries.

Excludes1

Not coded here. The listed conditions generally should not be reported together.

This code

Excludes2

Not included here. Both codes may be reported if the patient has both conditions.

Also from chapter/block level (8 notes)
Inherited from Chapter 11 Diseases of the digestive system
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Care settings

How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.

Home Health Primary

Accepted as the primary (principal) diagnosis on a home health claim. The Home Health Grouper assigns it to the MMTA - Gastrointestinal tract and Genitourinary system clinical group.

Source: CMS Home Health Grouper Software v07.2.26, effective October 1, 2026

Hospital CC

Counts as a complication or comorbidity (CC) when reported as a secondary diagnosis on an inpatient claim. It does not count when the principal diagnosis is one of the 7 codes in its exclusion list. Some MS-DRGs also ignore a CC or MCC that defines the DRG.

Source: CMS MS-DRG Definitions Manual v44, effective October 1, 2026, Appendix C

Includes

Further defines or gives examples of the content of the category.

Inherited from K61 Abscess of anal and rectal regions
  • abscess of anal and rectal regions
  • cellulitis of anal and rectal regions

Inclusion terms

Conditions classified to this code.

This code
  • Perirectal abscess

Alphabetic Index terms

Terms the official Alphabetic Index lists for this code. 6 entries