K61.1 Rectal abscess

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Applicable to

• Perirectal abscess

Excludes1 (never code together)

• ischiorectal abscess (K61.39)

Applies from K61 Abscess of anal and rectal regions

Includes

• abscess of anal and rectal regions
• cellulitis of anal and rectal regions

MS-DRG index

Defines the logic of DRG(s) 393-395 in MDC 06.

Approximate ICD-9-CM (GEMs)

• 566 Abscess of anal and rectal regions (approximate)

Code annotations containing back-references to K61.1

Back-references to K61

• Type 1 Excludes: K60 Fissure and fistula of anal and rectal regions ("fissure and fistula of anal and rectal regions with abscess or cellulitis (K61.-)")
• Type 2 Excludes: K60 Fissure and fistula of anal and rectal regions ("abscess or cellulitis of anal and rectal regions (K61.-)")
• Type 2 Excludes: K63.0 Abscess of intestine ("abscess of anal and rectal regions (K61.-)")
• Type 2 Excludes: L02 Cutaneous abscess, furuncle and carbuncle ("abscess of anus and rectal regions (K61.-)")
• Type 2 Excludes: L03 Cellulitis and acute lymphangitis ("cellulitis of anal and rectal region (K61.-)")
• Type 2 Excludes: L03.31 Cellulitis of trunk ("cellulitis of anal and rectal regions (K61.-)")

Diagnosis Index entries for K61.1

• Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) › intestine, intestinal NEC › rectal
• Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) › pararectal
• Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) › perirectal
• Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) › rectum
• Cellulitis (diffuse) (phlegmonous) (septic) (suppurative) › perirectal
• Cellulitis (diffuse) (phlegmonous) (septic) (suppurative) › rectum

Nearby codes

• K61 Abscess of anal and rectal regions
• K61.0 Anal abscess
• K61.1 Rectal abscess (this code)
• K61.2 Anorectal abscess
• K61.3 Ischiorectal abscess
• K61.31 Horseshoe abscess
• K61.39 Other ischiorectal abscess
• K61.4 Intrasphincteric abscess