2027 ICD-10-CM Diagnosis Code K64.5Perianal venous thrombosis

ICD-10-CM Codes›K00–K95›K55-K64›K64

ICD-10-CM K64.5
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

K64.5 is a billable ICD-10-CM diagnosis code for perianal venous thrombosis. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 393 through 395. Coders also document this condition as external hemorrhoids. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Hemorrhoids.

Code Identity

ICD-10-CM Code
K64.5
Billable Status
Yes — Valid for Submission
Code Describes
Perianal venous thrombosis
Short Description
Perianal venous thrombosis
Same as the full description in the CMS dataset.
Parent Code
K64
Hemorrhoids and perianal venous thrombosis

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK55-K64Other diseases of intestines
CategoryK64Hemorrhoids and perianal venous thrombosis
This CodeK64.5Perianal venous thrombosis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • External hemorrhoids
  • Hematoma of perianal region
  • Thrombosed external hemorrhoids
  • Thrombosed hemorrhoid incised
  • Thrombosed hemorrhoids
  • Thrombosed internal hemorrhoids

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to K64.5: its own notes plus those printed at K64 and Chapter 11. A note printed at a category, block or chapter applies to every code under it.

Includes

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

From K64 Hemorrhoids and perianal venous thrombosis applies to 8 codes
  • piles

Applicable To

Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.

  • External hemorrhoids with thrombosis
  • Perianal hematoma
  • Thrombosed hemorrhoids NOS

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From K64 Hemorrhoids and perianal venous thrombosis applies to 8 codes
  • hemorrhoids complicating childbirth and the puerperium (O87.2)
  • hemorrhoids complicating pregnancy (O22.4)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 11 (K00-K95) Diseases of the digestive system applies to 863 codes
  • 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)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name K64.5, its category, or a range that includes it.

Excludes2 1

These codes carry an Excludes2 note naming K64.5: its condition is not part of those codes, and both may be reported when the patient has both.

  • K62 Other diseases of anus and rectum
    hemorrhoids (K64.-) names K64.-, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR DIG014
Hemorrhoids
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Anal Disorders

Your anus is the opening at the end of your large intestine. It is where stool (poop) leaves your body.

The full article covers:

  • What is the anus?
  • What are anal disorders?
  • What are the symptoms of anal disorders?
  • How are anal disorders diagnosed?
  • How are anal disorders treated?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert K64.5 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
455.4 Ext thrombos hemorrhoid
Approximate The match is approximate rather than exact.
ICD-9-CM
455.7 Thrombos hemorrhoids NOS
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About K64.5Overview

What is the ICD-10 code for perianal venous thrombosis?

The ICD-10-CM code for perianal venous thrombosis is K64.5 (sometimes written as K645). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is K64.5 (Hemorrhoids and perianal venous thrombosis) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report perianal venous thrombosis on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does K64.5 group to?

When perianal venous thrombosis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 394, 395, 393, with relative weights from 0.6379 to 1.5877 depending on complications. Higher weights mean higher Medicare reimbursement.

Can K64.5 be reported with O87.2?

Not as a rule. The Excludes1 note at K64, which applies to K64.5, lists "hemorrhoids complicating childbirth and the puerperium (O87.2)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).

What is the ICD-9 equivalent of K64.5?

Under the General Equivalence Mappings, perianal venous thrombosis converts to ICD-9-CM 455.4 (ext thrombos hemorrhoid) and 455.7 (thrombos hemorrhoids NOS). The mapping is approximate, so confirm the match fits the documentation.