2027 ICD-10-CM Diagnosis Code I82.91Chronic embolism and thrombosis of unspecified vein

ICD-10-CM Codes›I00–I99›I80-I89›I82

ICD-10-CM I82.91
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

I82.91 is a billable ICD-10-CM diagnosis code for chronic embolism and thrombosis of unspecified vein. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 299 through 301. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 201 closely related codes. The code is flagged as an unspecified code, since codes identifying laterality exist in the same family. Coders also document this condition as chronic deep venous thrombosis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Chronic phlebitis; thrombophlebitis and thromboembolism.

Code Identity

ICD-10-CM Code
I82.91
Billable Status
Yes — Valid for Submission
Code Describes
Chronic embolism and thrombosis of unspecified vein
Short Description
Chronic embolism and thrombosis of unspecified vein
Same as the full description in the CMS dataset.
Parent Code
I82.9
Embolism and thrombosis of unspecified vein

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI80-I89Diseases of veins, lymphatic vessels and lymph nodes, not elsewhere classified
CategoryI82Other venous embolism and thrombosis
This CodeI82.91Chronic embolism and thrombosis of unspecified vein

Code EditsBilling

Medicare Code Editor checks that affect claim validity for I82.91.

Unspecified codes
Unspecified codes exist in the ICD-10-CM classification for circumstances when documentation in the medical record does not provide the level of detail needed to support reporting a more specific code. However, in the inpatient setting, there should generally be very limited and rare circumstances for which the laterality (right, left, bilateral) of a condition is unable to be documented and reported. The following pages contain the list of unspecified ICD-10-CM diagnosis codes for which there is a more specific code to identify laterality (right, left, bilateral) within that code family.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Chronic deep venous thrombosis
  • Chronic venous thrombosis

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to I82.91: its own notes plus those printed at I82 and Chapter 9. A note printed at a category, block or chapter applies to every code under it.

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 I82 Other venous embolism and thrombosis applies to 145 codes
  • venous embolism and thrombosis (of):
  • cerebral (I63.6, I67.6)
  • coronary (I21-I25)
  • intracranial and intraspinal, septic or NOS (G08)
  • intracranial, nonpyogenic (I67.6)
  • intraspinal, nonpyogenic (G95.1)
  • mesenteric (K55.0-)
  • portal (I81)
  • pulmonary (I26.-)
From Chapter 9 (I00-I99) Diseases of the circulatory system applies to 1,433 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)
  • systemic connective tissue disorders (M30-M36)
  • transient cerebral ischemic attacks and related syndromes (G45.-)

Code First

The underlying condition named in the note is sequenced before this code.

From I82 Other venous embolism and thrombosis applies to 145 codes
  • venous embolism and thrombosis complicating:
  • abortion, ectopic or molar pregnancy (O00-O07, O08.7)
  • pregnancy, childbirth and the puerperium (O22.-, O87.-)

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

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 CIR034
Chronic phlebitis; thrombophlebitis and thromboembolism
Default principal diagnosis: inpatient Yes · outpatient Yes

Convert I82.91 to ICD-9-CMHistory

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

ICD-9-CM
453.79 Ch emblsm veins NEC
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 I82.91Overview

What is the ICD-10 code for chronic embolism and thrombosis of unspecified vein?

The ICD-10-CM code for chronic embolism and thrombosis of unspecified vein is I82.91 (sometimes written as I8291). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is I82.91 (Embolism and thrombosis of unspecified vein) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report chronic embolism and thrombosis of unspecified vein on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does I82.91 group to?

When chronic embolism and thrombosis of unspecified vein is the principal diagnosis on an inpatient stay, it groups to MS-DRG 301, 300, 299, with relative weights from 0.7132 to 1.5840 depending on complications. Higher weights mean higher Medicare reimbursement.

Is I82.91 a CC or MCC?

CMS lists I82.91 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 201 closely related codes in its exclusion list.

What is coded first with I82.91?

The Code First note at I82, which applies to I82.91, reads: venous embolism and thrombosis complicating: abortion, ectopic or molar pregnancy (O00-O07, O08.7); pregnancy, childbirth and the puerperium (O22.-, O87.-). When one of these applies, it is sequenced before I82.91.