Anal and Rectal Fistulas

Coding for anal and rectal fistulas underwent significant expansion with the FY2025 code updates. This month’s “In the kNOW” will highlight these changes.

First, let’s define a fistula. An anal or rectal fistula is an abnormal passageway from those locations to the skin outside the body. It is usually the result of an abscess that is draining. See illustration below.

Source: https://fascrs.org/patients/diseases-and-conditions/a-z/abscess-and-fistula-expanded-information

Classification of the type of fistula is based on the level of involvement of the anal sphincter complex. The movement of stool is controlled by the muscles of the anal sphincter complex. As noted in the illustration below the classifications are:

• Superficial
• Intersphincteric
• Transssphincteric
• Suprasphincteric
• Extrasphincteric
  

Source: https://fascrs.org/patients/diseases-and-conditions/a-z/abscess-and-fistula-expanded-information

Until now, coding professionals have not been able to be this specific with the coding of anal and rectal fistulas. We simply assigned by the generic location of the fistula with codes as noted below.

K60.3 Anal fistula
K60.4 Rectal fistula
K60.5 Anorectal fistula

The October ICD-10-CM code updates now allow us to code based on severity by adding a 5th character to identify the fistula as either simple or complex as shown here.

K60.30 Anal fistula, unspecified
K60.31- Anal fistula, simple
K60.32- Anal fistula, complex

K60.40 Rectal fistula, unspecified
K60.41- Rectal fistula, simple
K60.42- Rectal fistula, complex

K60.50 Anorectal fistula, unspecified
K60.51- Anorectal fistula, simple
K60.52- Anorectal fistula, complex

The method of determining what is simple or complex is as follows:

Simple (1) = Low intersphincteric

 Superficial

Complex (2) = Extrasphincteric

    High intersphincteric

    Suprasphincteric

    Transsphincteric

Additionally, a 6th character categorizes each type of fistula as either:
Initial/new (1)
Persistent/chronic (2)
Recurrent/occurring after complete healing (3)
Unspecified (9)

A recurrent anal fistula described in dictation as being low intersphincteric would be coded as K60.313 Anal fistula, simple, recurrent. A transsphincteric rectal fistula that is new would be coded as K60.521 Rectal fistula, complex, initial.

 

Now you are In the kNOW!!

About the Author

Dianna Foley, RHIA, CHPS, CCS, CDIP, has 25 years of HIM experience. She earned her bachelor’s degree from the University of Cincinnati and holds RHIA, CHPS, CDIP, and CCS certifications from AHIMA. Dianna’s an AHIMA-approved ICD-10-CM/PCS trainer, an AHIMA-published author, a participant in AHIMA credential item writing and exam development, and served on the AHIMA Nominating Committee. Dianna has held various HIM positions and is now an independent coding consultant. She previously served as Eastern Gateway Community College’s program director for Medical Coding and HIT. She presents on coding topics at the national, state, and regional levels and serves as OHIMA’s Education Coordinator.