What is ICD-10 code I82.439?

I82.439 is the ICD-10-CM diagnosis code for Acute embolism and thrombosis of unspecified popliteal vein. A blood clot that suddenly forms in a knee-area vein (popliteal vein), but the specific side (right, left, or both) is not specified in the documentation. I82.439 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. I82.439 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. I82.439 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. I82.439 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

What is the V28 vs V24 difference for I82.439?

CMS phased in the V28 risk adjustment model over payment years 2024 (33%), 2025 (67%), and 2026 (100%), replacing V24. V28 consolidates HCC categories, removes some lower-acuity conditions, and recalibrates RAF weights across the entire model. For I82.439, V28 maps to Vascular Disease at RAF 0.356 while V24 mapped to Vascular Disease at RAF 0.297. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting I82.439?

Use only when laterality is truly unspecified or undocumented Attempt to clarify with provider documentation to assign more specific laterality code Because I82.439 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

I82.439 ICD-10 Code: Acute embolism and thrombosis

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupI82.439Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Diseases of the circulatory system (I00-I99) / Diseases of veins, lymphatic vessels and lymph nodes, not elsewhere classified (I80-I89)

I82.439

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Acute embolism and thrombosis of unspecified popliteal vein

A blood clot that suddenly forms in a knee-area vein (popliteal vein), but the specific side (right, left, or both) is not specified in the documentation.

Buddy Insight

Acute popliteal vein thrombosis is a proximal deep vein thrombosis located behind the knee that carries significant risk of clot extension and pulmonary embolism.

CMS-HCC V28

Mapped

HCC 267

Vascular Disease

RAF 0.356

CMS-HCC V24

Mapped

HCC 108

Vascular Disease

RAF 0.297

ACA/HHS

Not risk-adjusted for this model/period.

RAF 0

ESRD/PACE

Mapped

HCC 108

Vascular Disease

RAF 0.0

RXHCC

Mapped

HCC 215

Pulmonary Embolism and Other ...

RAF 0.0

Code Trumping

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Code Book Path

Official

I82.4Acute embolism and thrombosis of deep veins of lower extremity

I82.43Acute embolism and thrombosis of popliteal vein

I82.439Acute embolism and thrombosis of unspecified popliteal vein

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for I82.439 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for I82.439 in this effective period.

Related Child Codes

Official

I82.431Acute embolism and thrombosis of right popliteal vein

I82.432Acute embolism and thrombosis of left popliteal vein

I82.433Acute embolism and thrombosis of popliteal vein, bilateral

Includes

Official

ICD-10-CM does not list Includes notes for I82.439 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for I82.439 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for I82.439 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for I82.439 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for I82.439 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Clinical diagnosis of venous thrombosis or thrombophlebitis clearly documented by the treating provider

Diagnostic confirmation via duplex ultrasonography, CT venography, MR venography, or venography with imaging findings described

Current treatment plan including anticoagulation regimen with specific medication, dose, and duration

Documentation of acute onset with date of symptom onset or diagnosis establishing the acute nature

MEAT Support

HCC Buddy guidance

Clinical diagnosis of venous thrombosis or thrombophlebitis clearly documented by the treating provider

Diagnostic confirmation via duplex ultrasonography, CT venography, MR venography, or venography with imaging findings described

Current treatment plan including anticoagulation regimen with specific medication, dose, and duration

Documentation of acute onset with date of symptom onset or diagnosis establishing the acute nature

Audit Caution

HCC Buddy guidance

Confusing acute and chronic thrombosis status; acute indicates new onset within the current care episode, while chronic indicates a persistent or recurrent clot documented over time

Defaulting to the unspecified laterality code without querying the provider; laterality is almost always determinable from imaging reports and should be specified

Failing to assign a separate code for pulmonary embolism (I26.-) when documented as a complication of the deep vein thrombosis

Not coding current anticoagulant therapy status (Z79.01) or history of venous thromboembolism (Z86.718) as additional diagnoses when applicable

Common Mistakes

HCC Buddy guidance

I82.411-I82.419 — Femoral vein thrombosis; femoral vein is above the knee (proximal to popliteal)

I82.441-I82.449 — Tibial vein thrombosis; tibial veins are below the knee (distal to popliteal)

I80.20-I80.29 — Phlebitis of other deep vessels; use for thrombophlebitis rather than thrombosis/embolism

I82.401-I82.409 — Unspecified deep vein DVT; use only when specific vein location is unknown

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

Is I82.439 an HCC code?

Yes. I82.439 maps to Vascular Disease under the CMS-HCC V28 risk adjustment model (and Vascular Disease under V24).

HCC Category Mapping

V28HCC 267, Vascular Disease

0.356

V24HCC 108, Vascular Disease

0.297

ESRDHCC 108, Vascular Disease

0.000

RxHCCHCC 215, Pulmonary Embolism and Other Vascular Disease

0.000

RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

MEAT Criteria for I82.439

For I82.439to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
EEvaluate: test results, medication response, or physical findings reviewed by the provider
AAssess: explicit mention in the assessment or plan with acknowledgment of status
TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed I82.439 during that encounter, not just copy-forwarded from a problem list.

What This Code Means

I82.439 is the ICD-10-CM diagnosis code for acute embolism and thrombosis of unspecified popliteal vein. A blood clot that suddenly forms in a knee-area vein (popliteal vein), but the specific side (right, left, or both) is not specified in the documentation. I82.439 sits in the ICD-10-CM chapter for diseases of the circulatory system (i00-i99), within the section covering diseases of veins, lymphatic vessels and lymph nodes, not elsewhere classified (i80-i89).

Under the CMS-HCC V28 risk adjustment model, I82.439 maps to Vascular Disease (HCC 267) with a community, non-dual, aged base RAF weight of 0.356. Under the older V24 model, I82.439 mapped to the same category but with a base RAF weight of 0.297, V28 recalibrated weights across the entire model. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.

Use only when laterality is truly unspecified or undocumented. Because I82.439 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for I82.439 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Use only when laterality is truly unspecified or undocumented
•Attempt to clarify with provider documentation to assign more specific laterality code

Clinical Significance

Acute popliteal vein thrombosis is a proximal deep vein thrombosis located behind the knee that carries significant risk of clot extension and pulmonary embolism. The popliteal vein is the transition point between distal and proximal deep veins, and thrombosis here requires prompt anticoagulation therapy. Accurate capture ensures proper risk stratification reflecting the acute vascular event and associated care needs.

Documentation Requirements

✓Clinical diagnosis of venous thrombosis or thrombophlebitis clearly documented by the treating provider
✓Diagnostic confirmation via duplex ultrasonography, CT venography, MR venography, or venography with imaging findings described
✓Current treatment plan including anticoagulation regimen with specific medication, dose, and duration
✓Documentation of acute onset with date of symptom onset or diagnosis establishing the acute nature
✓Laterality documentation should be sought; if unavailable, document the reason laterality cannot be determined
✓Assessment of risk factors (immobility, recent surgery, malignancy, hypercoagulable state, oral contraceptive use)

Commonly Confused Codes

•I82.411-I82.419: Femoral vein thrombosis; femoral vein is above the knee (proximal to popliteal)
•I82.441-I82.449: Tibial vein thrombosis; tibial veins are below the knee (distal to popliteal)
•I80.20-I80.29: Phlebitis of other deep vessels; use for thrombophlebitis rather than thrombosis/embolism
•I82.401-I82.409: Unspecified deep vein DVT; use only when specific vein location is unknown
•I82.531-I82.539: Chronic popliteal vein thrombosis; verify acute vs. chronic status