What is ICD-10 code I82.423?

I82.423 is the ICD-10-CM diagnosis code for Acute embolism and thrombosis of iliac vein, bilateral. A blood clot that suddenly forms in both pelvic veins (iliac veins), blocking blood flow in both lower abdomen and legs. I82.423 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. I82.423 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. I82.423 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. I82.423 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.

Which HCC does I82.423 map to under V28?

I82.423 maps to CMS-HCC V28 267 (Deep Vein Thrombosis and Pulmonary Embolism). The category number and label come from the CMS-HCC V28 model file for payment year 2026.

What does I82.423 pay in RAF?

I82.423 carries a community, non-dual, aged (CNA) RAF weight of 0.294 under CMS-HCC V28 for payment year 2026. The weight comes from the CMS V28 relative-factor file, not a hand-typed table.

What is the V28 vs V24 difference for I82.423?

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 I82.423, V28 maps to Deep Vein Thrombosis and Pulmonary Embolism at RAF 0.294 while V24 mapped to Vascular Disease at RAF 0.288. Both models can still appear in legacy data and in payer-specific lookback periods.

2026 ICD-10-CM I82.423: Acute embolism

I82.423 maps to CMS-HCC V28 267 (RAF 0.294). Documentation must support MEAT. MEAT criteria · RAF calculator · HCC Buddy coding tools

ICD-10-CM Code View

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Code lookupI82.423Effective 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)

I82.423

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

Acute embolism and thrombosis of iliac vein, bilateral

A blood clot that suddenly forms in both pelvic veins (iliac veins), blocking blood flow in both lower abdomen and legs.

Buddy Insight

Acute iliac vein thrombosis is a proximal deep vein thrombosis involving the pelvic veins, carrying the highest risk of pulmonary embolism among lower extremity deep vein thrombosis.

CMS-HCC V28

Mapped

HCC 267

Deep Vein Thrombosis and Pulm...

RAF 0.294

CMS-HCC V24

Mapped

HCC 108

Vascular Disease

RAF 0.288

ACA/HHS

Mapped

HCC 156

HHS-HCC 156

Varies by metal level

ESRD/PACE

Mapped

HCC 108

Vascular Disease

RAF 0.073

RXHCC

Mapped

HCC 215

Pulmonary Embolism and Other ...

RAF 0.228

Code Book Path

Official

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

I82.42Acute embolism and thrombosis of iliac vein

I82.423Acute embolism and thrombosis of iliac vein, bilateral

Inclusion Terms

Official

Acute embolism and thrombosis of common iliac vein
Acute embolism and thrombosis of external iliac vein
Acute embolism and thrombosis of internal iliac vein

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for I82.423 in this effective period.

Related Child Codes

Official

I82.421Acute embolism and thrombosis of right iliac vein

I82.422Acute embolism and thrombosis of left iliac vein

I82.429Acute embolism and thrombosis of unspecified iliac vein

Includes

Official

ICD-10-CM does not list Includes notes for I82.423 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for I82.423 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for I82.423 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for I82.423 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for I82.423 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

Assigning the bilateral code when only one extremity is affected; bilateral codes require explicit documentation of both-sided involvement

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 veins are distal to iliac veins in the thigh

I82.220/I82.221 — Inferior vena cava thrombosis; IVC is above the iliac bifurcation

I74.5 — Embolism and thrombosis of iliac artery; arterial not venous occlusion

I82.401-I82.409 — Unspecified deep vein DVT of lower extremity; use when specific vein is not identified

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is I82.423 an HCC code?

Yes. I82.423 (Acute embolism and thrombosis of iliac vein, bilateral) maps to Deep Vein Thrombosis and Pulmonary Embolism under the CMS-HCC V28 risk adjustment model (and Vascular Disease under V24), with a community non-dual aged RAF of 0.294. It is billable for payment year 2026.

Coder answer: I82.423 is billable and maps to V28 HCC 267, Deep Vein Thrombosis and Pulmonary Embolism. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: I82.423
Description: Acute embolism and thrombosis of iliac vein, bilateral
HCC (V28): HCC 267 — Deep Vein Thrombosis and Pulmonary Embolism
RAF: 0.294
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 267, Deep Vein Thrombosis and Pulmonary Embolism

0.294

V24HCC 108, Vascular Disease

0.288

ESRDHCC 108, Vascular Disease

0.073

RxHCCHCC 215, Pulmonary Embolism and Other Vascular Disease

0.228

Each model's RAF is its CMS base weight for that model's standard population, so weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. 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.

Work I82.423 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for I82.423

For I82.423 to 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 I82.423 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

I82.423 is the ICD-10-CM diagnosis code for acute embolism and thrombosis of iliac vein, bilateral. A blood clot that suddenly forms in both pelvic veins (iliac veins), blocking blood flow in both lower abdomen and legs. I82.423 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, I82.423 maps to Deep Vein Thrombosis and Pulmonary Embolism (HCC 267) with a community, non-dual, aged base RAF weight of 0.294. Under the older CMS-HCC V24 model, I82.423 maps to Vascular Disease (HCC 108) with a community, non-dual, aged base RAF weight of 0.288. 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.

Only assign when bilateral iliac vein thrombosis is explicitly documented. Because I82.423 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 I82.423 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Only assign when bilateral iliac vein thrombosis is explicitly documented
•Verify this is not a case of unilateral thrombosis that was miscoded

Clinical Significance

Acute iliac vein thrombosis is a proximal deep vein thrombosis involving the pelvic veins, carrying the highest risk of pulmonary embolism among lower extremity deep vein thrombosis. These patients often require aggressive intervention including catheter-directed thrombolysis, IVC filter consideration, and intensive anticoagulation. This diagnosis reflects critical vascular disease severity important for accurate risk stratification.

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
✓Explicit documentation that both lower extremities are affected
✓Assessment of risk factors (immobility, recent surgery, malignancy, hypercoagulable state, oral contraceptive use)

Commonly Confused Codes

•I82.411-I82.419: Femoral vein thrombosis; femoral veins are distal to iliac veins in the thigh
•I82.220/I82.221: Inferior vena cava thrombosis; IVC is above the iliac bifurcation
•I74.5: Embolism and thrombosis of iliac artery; arterial not venous occlusion
•I82.401-I82.409: Unspecified deep vein DVT of lower extremity; use when specific vein is not identified
•I82.531-I82.539: Chronic embolism of iliac vein; verify acute vs. chronic presentation