What is ICD-10 code I74.9?

I74.9 is the ICD-10-CM diagnosis code for Embolism and thrombosis of unspecified artery. It belongs to the ICD-10-CM chapter for diseases of the circulatory system (i00-i99). I74.9 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. I74.9 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. I74.9 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. I74.9 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 I74.9?

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 I74.9, V28 maps to Vascular Disease with Complications at RAF 0.455 while V24 mapped to Vascular Disease with Complications at RAF 0.383. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting I74.9?

Avoid using this unspecified code when possible; query the provider to identify the specific artery involved (e.g., I74.0 for aorta, I74.1 for iliac artery) for more accurate coding This code should only be used when documentation truly does not specify the artery location; check all clinical notes, imaging reports, and provider documentation before defaulting to the unspecified code Because I74.9 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.

2026 ICD-10-CM I74.9: Embolism and thrombosis

ICD-10-CM Code View

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Code lookupI74.9Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Diseases of the circulatory system (I00-I99) / Diseases of arteries, arterioles and capillaries (I70-I79)

I74.9

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

Embolism and thrombosis of unspecified artery

A blood clot has formed in an artery somewhere in the body, but the specific artery location is not documented. This condition blocks blood flow and can be life-threatening depending on which artery is affected.

Buddy Insight

Embolism and thrombosis of unspecified artery indicates an acute arterial occlusive event where the specific artery has not been documented.

CMS-HCC V28

Mapped

HCC 264

Vascular Disease with Complic...

RAF 0.455

CMS-HCC V24

Mapped

HCC 107

Vascular Disease with Complic...

RAF 0.383

ACA/HHS

Mapped

HCC 154

HHS-HCC 154

Varies by metal level

ESRD/PACE

Mapped

HCC 107

Vascular Disease with Complic...

RAF 0.144

RXHCC

N/A

—

Not risk-adjusted for this model/period.

Not mapped

Code Book Path

Official

I74Arterial embolism and thrombosis

I74.9Embolism and thrombosis of unspecified artery

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for I74.9 in this effective period.

Excludes 2

Official

atheroembolism (I75.-)
basilar embolism and thrombosis (I63.0-I63.2, I65.1)
carotid embolism and thrombosis (I63.0-I63.2, I65.2)
cerebral embolism and thrombosis (I63.3-I63.5, I66.-)
coronary embolism and thrombosis (I21-I25)

Related Child Codes

Official

I74.0Embolism and thrombosis of abdominal aorta

I74.1Embolism and thrombosis of other and unspecified parts of aorta

I74.2Embolism and thrombosis of arteries of the upper extremities

I74.3Embolism and thrombosis of arteries of the lower extremities

I74.4Embolism and thrombosis of arteries of extremities, unspecified

Includes

Official

embolic infarction
embolic occlusion
thrombotic infarction
thrombotic occlusion

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for I74.9 in this effective period.

Code First

Official

embolism and thrombosis complicating abortion or ectopic or molar pregnancy (O00-O07, O08.2)
embolism and thrombosis complicating pregnancy, childbirth and the puerperium (O88.-)

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for I74.9 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for I74.9 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Documentation of arterial embolism or thrombosis

Attempt to determine the specific artery from imaging, operative, or clinical notes

Clinical presentation of acute arterial occlusion

Query provider for vessel specification

MEAT Support

HCC Buddy guidance

Documentation of arterial embolism or thrombosis

Attempt to determine the specific artery from imaging, operative, or clinical notes

Clinical presentation of acute arterial occlusion

Query provider for vessel specification

Audit Caution

HCC Buddy guidance

Accepting this unspecified code without exhaustively reviewing imaging and operative documentation for artery identification

Confusing arterial thromboembolism with venous thromboembolism — completely different code categories

Not querying the provider when clinical documentation describes acute limb ischemia without naming the occluded vessel

Using this code for chronic arterial occlusion rather than acute thromboembolic events

Common Mistakes

HCC Buddy guidance

I74.2 — Embolism and thrombosis of arteries of the upper extremities: use when upper extremity artery is specified

I74.3 — Embolism and thrombosis of arteries of the lower extremities: use when lower extremity artery is specified

I74.8 — Embolism and thrombosis of other arteries: use when artery is named but not elsewhere classified

I82.90 — Acute embolism and thrombosis of unspecified vein: venous, not arterial

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 I74.9 an HCC code?

Yes. I74.9 (Embolism and thrombosis of unspecified artery) maps to Vascular Disease with Complications under the CMS-HCC V28 risk adjustment model (and Vascular Disease with Complications under V24), with a community non-dual aged RAF of 0.455. It is billable for payment year 2026.

Coder answer: I74.9 is billable and maps to V28 HCC 264, Vascular Disease with Complications. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: I74.9
Description: Embolism and thrombosis of unspecified artery
HCC (V28): HCC 264 — Vascular Disease with Complications
RAF: 0.455
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 264, Vascular Disease with Complications

0.455

V24HCC 107, Vascular Disease with Complications

0.383

ESRDHCC 107, Vascular Disease with Complications

0.144

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 I74.9 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for I74.9

For I74.9 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 I74.9 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

I74.9 is the ICD-10-CM diagnosis code for embolism and thrombosis of unspecified artery. A blood clot has formed in an artery somewhere in the body, but the specific artery location is not documented. This condition blocks blood flow and can be life-threatening depending on which artery is affected. I74.9 sits in the ICD-10-CM chapter for diseases of the circulatory system (i00-i99), within the section covering diseases of arteries, arterioles and capillaries (i70-i79).

Under the CMS-HCC V28 risk adjustment model, I74.9 maps to Vascular Disease with Complications (HCC 264) with a community, non-dual, aged base RAF weight of 0.455. Under the older V24 model, I74.9 mapped to the same category but with a base RAF weight of 0.383, 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.

Avoid using this unspecified code when possible; query the provider to identify the specific artery involved (e.g., I74.0 for aorta, I74.1 for iliac artery) for more accurate coding. Because I74.9 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 I74.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Avoid using this unspecified code when possible; query the provider to identify the specific artery involved (e.g., I74.0 for aorta, I74.1 for iliac artery) for more accurate coding
•This code should only be used when documentation truly does not specify the artery location; check all clinical notes, imaging reports, and provider documentation before defaulting to the unspecified code

Clinical Significance

Embolism and thrombosis of unspecified artery indicates an acute arterial occlusive event where the specific artery has not been documented. While this still captures the vascular complication for risk adjustment, the lack of specificity should prompt a thorough review of all available documentation to identify the affected vessel. Acute arterial occlusion is always a significant clinical event.

Documentation Requirements

✓Documentation of arterial embolism or thrombosis
✓Attempt to determine the specific artery from imaging, operative, or clinical notes
✓Clinical presentation of acute arterial occlusion
✓Query provider for vessel specification
✓Treatment documentation
✓Source evaluation when applicable

Commonly Confused Codes

•I74.2: Embolism and thrombosis of arteries of the upper extremities: use when upper extremity artery is specified
•I74.3: Embolism and thrombosis of arteries of the lower extremities: use when lower extremity artery is specified
•I74.8: Embolism and thrombosis of other arteries: use when artery is named but not elsewhere classified
•I82.90: Acute embolism and thrombosis of unspecified vein: venous, not arterial