What is ICD-10 code F79?

F79 is the ICD-10-CM diagnosis code for Unspecified intellectual disabilities. Intellectual disability where the specific cause or severity level cannot be determined or is not documented. This is a catch-all code for intellectual disabilities that don't meet criteria for more specific diagnoses. F79 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. F79 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. F79 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. F79 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 F79?

F79 does not map to a payment HCC under either the CMS-HCC V28 risk adjustment model or the older V24 model. V28 reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition. Because neither model rewards F79 with a risk adjustment factor, it contributes zero to a Medicare Advantage beneficiary's RAF score in either version. Coders should check whether provider documentation supports a more specific child code that does map to a payment HCC.

What should coders know when reporting F79?

Avoid using this code if the cause (genetic, environmental, or other) can be identified; use more specific codes instead Query the provider if additional information about severity or etiology is available to allow for more precise coding

F79: Unspecified intellectual disabilities — ICD-10

ICD-10-CM Code View

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Code lookupF79Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Mental, Behavioral and Neurodevelopmental disorders (F01-F99) / Intellectual Disabilities (F70-F79)

F79

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

Unspecified intellectual disabilities

Intellectual disability where the specific cause or severity level cannot be determined or is not documented. This is a catch-all code for intellectual disabilities that don't meet criteria for more specific diagnoses.

Buddy Insight

Unspecified intellectual disability is used when the provider documents intellectual disability without specifying the severity level (mild, moderate, severe, or profound).

CMS-HCC V28

Not risk-adjusted for this model/period.

RAF 0

CMS-HCC V24

Not risk-adjusted for this model/period.

RAF 0

ACA/HHS

Not risk-adjusted for this model/period.

RAF 0

ESRD/PACE

Not risk-adjusted for this model/period.

RAF 0

RXHCC

Mapped

HCC 148

Mild Intellectual Disabilities

RAF 0.0

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Code Book Path

Official

F7Intellectual Disabilities (F70-F79)

F79Unspecified intellectual disabilities

Inclusion Terms

Official

Mental deficiency NOS
Mental subnormality NOS

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for F79 in this effective period.

Related Child Codes

Official

ICD-10-CM does not list child codes under F79 for this display context.

Includes

Official

ICD-10-CM does not list Includes notes for F79 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for F79 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for F79 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for F79 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for F79 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Provider documentation of intellectual disability diagnosis

Evidence of deficits in both intellectual and adaptive functioning with onset during the developmental period

Query opportunity — always attempt to obtain severity specification from the provider

Documentation of current functional status and support needs

MEAT Support

HCC Buddy guidance

Provider documentation of intellectual disability diagnosis

Evidence of deficits in both intellectual and adaptive functioning with onset during the developmental period

Query opportunity — always attempt to obtain severity specification from the provider

Documentation of current functional status and support needs

Audit Caution

HCC Buddy guidance

Defaulting to F79 when the provider has specified severity — always use F70-F73 when severity is documented

Coding borderline intellectual functioning (R41.83) as intellectual disability — IQ 71-84 does not qualify

Failing to query the provider for severity specification when the patient has formal cognitive testing on file

Using F79 for cognitive decline in elderly patients — acquired cognitive impairment is coded differently from developmental intellectual disability

Common Mistakes

HCC Buddy guidance

F70-F73 — Specified severity intellectual disabilities; always prefer the severity-specific code when documentation supports it

R41.83 — Borderline intellectual functioning; IQ 71-84, does not meet criteria for intellectual disability

F88 — Other disorders of psychological development; developmental delays may not meet criteria for intellectual disability

F81.x — Specific developmental disorders of scholastic skills; learning disabilities are not intellectual disability

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 F79 an HCC code?

No. F79 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.

HCC Category Mapping

RxHCCHCC 148, Mild Intellectual Disabilities

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.

Work F79 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for F79

For F79to 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 F79 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

F79 is the ICD-10-CM diagnosis code for unspecified intellectual disabilities. Intellectual disability where the specific cause or severity level cannot be determined or is not documented. This is a catch-all code for intellectual disabilities that don't meet criteria for more specific diagnoses. F79 sits in the ICD-10-CM chapter for mental, behavioral and neurodevelopmental disorders (f01-f99), within the section covering intellectual disabilities (f70-f79).

F79 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.

This code does not map to a CMS-HCC V28 payment category. Capture depends on documentation that supports the diagnosis; verify the HCC assignment against the current CMS mapping for the applicable payment year. Coders reviewing F79 should check whether additional documentation would support a more specific child code in the same hierarchy that does map to a payment HCC, capturing the correct specificity is the highest-impact RAF improvement available within accurate coding.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for F79 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Avoid using this code if the cause (genetic, environmental, or other) can be identified; use more specific codes instead
•Query the provider if additional information about severity or etiology is available to allow for more precise coding

Clinical Significance

Unspecified intellectual disability is used when the provider documents intellectual disability without specifying the severity level (mild, moderate, severe, or profound). While acceptable in certain clinical contexts, this code provides less information for care planning. Intellectual disability requires lifelong support and is associated with increased comorbid medical and psychiatric conditions.

Documentation Requirements

✓Provider documentation of intellectual disability diagnosis
✓Evidence of deficits in both intellectual and adaptive functioning with onset during the developmental period
✓Query opportunity — always attempt to obtain severity specification from the provider
✓Documentation of current functional status and support needs
✓Assessment of comorbid conditions

Commonly Confused Codes

•F70-F73: Specified severity intellectual disabilities; always prefer the severity-specific code when documentation supports it
•R41.83: Borderline intellectual functioning; IQ 71-84, does not meet criteria for intellectual disability
•F88: Other disorders of psychological development; developmental delays may not meet criteria for intellectual disability
•F81.x: Specific developmental disorders of scholastic skills; learning disabilities are not intellectual disability

Code Hierarchy

└F79Unspecified intellectual disabilities

F79 ICD-10-CM Code: Unspecified intellectual disabilities

HCC Buddy Code Card

F79

Is F79 an HCC code?

HCC Category Mapping

MEAT Criteria for F79

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What This Code Means

Coding Tips

Clinical Significance

Documentation Requirements

Commonly Confused Codes

Code Hierarchy

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