2026 ICD-10-CM Diagnosis Code I80.3Phlebitis and thrombophlebitis of lower extremities, unspecified

ICD-10-CM Codes›I00–I99›I80-I89›I80

ICD-10-CM I80.3
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

I80.3 is a billable ICD-10-CM diagnosis code for phlebitis and thrombophlebitis of lower extremities, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 299 through 301. Coders also document this condition as bilateral lower limb vein thrombophlebitis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Acute phlebitis; thrombophlebitis and thromboembolism.

Code Identity

ICD-10-CM Code
I80.3
Billable Status
Yes — Valid for Submission
Code Describes
Phlebitis and thrombophlebitis of lower extremities, unspecified
Short Description
Phlebitis and thrombophlebitis of lower extremities, unsp
Parent Code
I80
Phlebitis and thrombophlebitis

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI80-I89Diseases of veins, lymphatic vessels and lymph nodes, not elsewhere classified
CategoryI80Phlebitis and thrombophlebitis
This CodeI80.3Phlebitis and thrombophlebitis of lower extremities, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bilateral lower limb vein thrombophlebitis
  • Left lower limb vein thrombophlebitis
  • Phlebitis of lower limb vein
  • Right lower limb vein thrombophlebitis
  • Thrombophlebitis of lower extremities

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Phlebitis(infective) (pyemic) (septic) (suppurative)
      • leg
    • Thrombophlebitis
      • leg

Clinical ClassificationClinical

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

CCSR CIR033
Acute phlebitis; thrombophlebitis and thromboembolism
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Deep Vein Thrombosis

Deep vein thrombosis, or DVT, is a blood clot that forms in a vein deep in the body. Most deep vein clots occur in the lower leg or thigh. If the vein swells, the condition is called thrombophlebitis. A deep vein thrombosis can break loose and cause a serious problem in the lung, called a pulmonary embolism.

Read the full article at MedlinePlus

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

Convert I80.3 to ICD-9-CMHistory

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

ICD-9-CM
451.2 Thrombophlebitis leg NOS
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About I80.3Overview

Is I80.3 (Phlebitis and thrombophlebitis) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report phlebitis and thrombophlebitis of lower extremities, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does I80.3 group to?

When phlebitis and thrombophlebitis of lower extremities, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 299, 300, 301, with relative weights from 0.7197 to 1.6327 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of I80.3?

Under the General Equivalence Mappings, phlebitis and thrombophlebitis of lower extremities, unspecified converts to ICD-9-CM 451.2 (thrombophlebitis leg NOS). The mapping is a direct match.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.