What is ICD-10 code I78.0?

I78.0 is the ICD-10-CM diagnosis code for Hereditary hemorrhagic telangiectasia. It belongs to the ICD-10-CM chapter for diseases of the circulatory system (i00-i99). I78.0 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. I78.0 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. I78.0 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. I78.0 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 I78.0 map to under V28?

I78.0 does not map to a CMS-HCC V28 payment category. Check the current CMS-HCC V28 model file for payment year 2026 rather than an older V24 tip sheet.

What does I78.0 pay in RAF?

I78.0 has no separately stated V28 community RAF weight. If it is not a V28 payment HCC, it adds nothing to a community RAF score.

What is the V28 vs V24 difference for I78.0?

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. I78.0 was a payment HCC under V24 (Vascular Disease) but the V28 recalibration removed it from the risk adjustment model. Both models can still appear in legacy data and in payer-specific lookback periods.

What documentation supports I78.0?

This is a hereditary condition, so document family history when available to support the diagnosis and differentiate from acquired telangiectasia Specify the affected site(s) if documented (e.g., pulmonary, cerebral, gastrointestinal involvement) as these may have separate codes or require additional documentation for complications Because I78.0 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. See the MEAT criteria checklist at /meat-criteria for what Monitor, Evaluate, Assess, or Treat looks like in a note. MEAT is generic documentation evidence, not a payer-specific rule.

2026 ICD-10-CM I78.0: Hereditary hemorrhagic

I78.0 is not a CMS-HCC payment code. MEAT criteria · RAF calculator · free HCC coding tools

ICD-10-CM Code View

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Code lookupI78.0Effective 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)

I78.0

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

Hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia is an inherited genetic disorder that causes abnormal blood vessels to form in the skin and internal organs, leading to frequent nosebleeds and other bleeding problems. People with this condition are born with it and may experience bleeding episodes throughout their lives.

Buddy Insight

CMS-HCC V28

N/A

—

Not risk-adjusted for this model/period.

Not mapped

CMS-HCC V24

Mapped

HCC 108

Vascular Disease

RAF 0.288

ACA/HHS

N/A

—

Not risk-adjusted for this model/period.

Not mapped

ESRD/PACE

Mapped

HCC 108

Vascular Disease

RAF 0.073

RXHCC

N/A

—

Not risk-adjusted for this model/period.

Not mapped

Code Book Path

Official

I78Diseases of capillaries

I78.0Hereditary hemorrhagic telangiectasia

Inclusion Terms

Official

Rendu-Osler-Weber disease

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for I78.0 in this effective period.

Related Child Codes

Official

I78.1Nevus, non-neoplastic

I78.8Other diseases of capillaries

I78.9Disease of capillaries, unspecified

Includes

Official

ICD-10-CM does not list Includes notes for I78.0 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for I78.0 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for I78.0 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for I78.0 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for I78.0 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Clinical diagnosis based on Curacao criteria: spontaneous recurrent epistaxis, mucocutaneous telangiectasias, visceral involvement, family history

Genetic testing results when available (endoglin, activin receptor-like kinase 1, or SMAD4 mutations)

Documentation of organ involvement including pulmonary, hepatic, or cerebral arteriovenous malformations

Iron studies and hemoglobin levels for chronic blood loss assessment

MEAT Support

HCC Buddy guidance

Clinical diagnosis based on Curacao criteria: spontaneous recurrent epistaxis, mucocutaneous telangiectasias, visceral involvement, family history

Genetic testing results when available (endoglin, activin receptor-like kinase 1, or SMAD4 mutations)

Documentation of organ involvement including pulmonary, hepatic, or cerebral arteriovenous malformations

Iron studies and hemoglobin levels for chronic blood loss assessment

Audit Caution

HCC Buddy guidance

Coding only the symptom (epistaxis R04.0) without the underlying hereditary hemorrhagic telangiectasia diagnosis

Failing to code associated iron deficiency anemia from chronic blood loss

Not coding organ-specific arteriovenous malformation involvement separately when documented

Confusing isolated telangiectasias with hereditary hemorrhagic telangiectasia — hereditary hemorrhagic telangiectasia requires meeting diagnostic criteria

Common Mistakes

HCC Buddy guidance

I78.1 — Nevus, non-neoplastic: benign skin vascular lesion, not hereditary hemorrhagic telangiectasia

I78.8 — Other diseases of capillaries: other capillary disorders not classified as hereditary hemorrhagic telangiectasia

D68.0 — Von Willebrand disease: different hereditary bleeding disorder

R04.0 — Epistaxis: symptom code only; use I78.0 for the underlying hereditary hemorrhagic telangiectasia diagnosis

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 I78.0 an HCC code?

Yes. I78.0 maps to Vascular Disease under the V24 model but is not retained in V28.

Code: I78.0
Description: Hereditary hemorrhagic telangiectasia
HCC (V28): No CMS-HCC V28 mapping
RAF: —
Billable: Yes
Payment year: 2026

HCC Category Mapping

V24HCC 108, Vascular Disease

0.288

ESRDHCC 108, Vascular Disease

0.073

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 I78.0 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for I78.0

For I78.0 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 I78.0 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

I78.0 is the ICD-10-CM diagnosis code for hereditary hemorrhagic telangiectasia. Hereditary hemorrhagic telangiectasia is an inherited genetic disorder that causes abnormal blood vessels to form in the skin and internal organs, leading to frequent nosebleeds and other bleeding problems. People with this condition are born with it and may experience bleeding episodes throughout their lives. I78.0 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 older CMS-HCC V24 model, I78.0 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.

This is a hereditary condition, so document family history when available to support the diagnosis and differentiate from acquired telangiectasia. Because I78.0 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 I78.0 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•This is a hereditary condition, so document family history when available to support the diagnosis and differentiate from acquired telangiectasia
•Specify the affected site(s) if documented (e.g., pulmonary, cerebral, gastrointestinal involvement) as these may have separate codes or require additional documentation for complications

Clinical Significance

Hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu disease) is a genetic disorder causing abnormal blood vessel formations (arteriovenous malformations) throughout the body, leading to recurrent epistaxis, gastrointestinal bleeding, and potential organ involvement. This chronic condition requires lifelong management and surveillance for pulmonary and cerebral arteriovenous malformations, reflecting ongoing resource utilization.

Documentation Requirements

✓Clinical diagnosis based on Curacao criteria: spontaneous recurrent epistaxis, mucocutaneous telangiectasias, visceral involvement, family history
✓Genetic testing results when available (endoglin, activin receptor-like kinase 1, or SMAD4 mutations)
✓Documentation of organ involvement including pulmonary, hepatic, or cerebral arteriovenous malformations
✓Iron studies and hemoglobin levels for chronic blood loss assessment
✓Screening schedule for pulmonary and cerebral arteriovenous malformations
✓Current treatment plan including iron supplementation, transfusions, or procedural interventions

Commonly Confused Codes

•I78.1: Nevus, non-neoplastic: benign skin vascular lesion, not hereditary hemorrhagic telangiectasia
•I78.8: Other diseases of capillaries: other capillary disorders not classified as hereditary hemorrhagic telangiectasia
•D68.0: Von Willebrand disease: different hereditary bleeding disorder
•R04.0: Epistaxis: symptom code only; use I78.0 for the underlying hereditary hemorrhagic telangiectasia diagnosis