Yes. F91.3 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. F91.3 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 F91.3?

F91.3 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 community model rewards F91.3 with a risk adjustment factor, it contributes zero to a Medicare Advantage beneficiary's V28/V24 community RAF score in either version. It does, however, map under the Part D RxHCC model (Personality Disorders, Anxiety, and Other Specified Mental Disorders), which affects the ESRD and/or Part D (RxHCC) risk scores. Coders should check whether provider documentation supports a more specific child code that does map to a community payment HCC.

What should coders know when reporting F91.3?

Distinguish from conduct disorder by confirming absence of serious aggression, property destruction, or violation of others' rights Document specific oppositional behaviors such as arguing, defiance, and anger outbursts

2026 ICD-10-CM F91.3: Oppositional defiant disorder

ICD-10-CM Code View

HCC Buddy Code Card

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Code lookupF91.3Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Mental, Behavioral and Neurodevelopmental disorders (F01-F99) / Behavioral and emotional disorders with onset usually occurring in childhood and adolescence (F90-F98)

F91.3

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

Oppositional defiant disorder

A behavioral disorder characterized by a persistent pattern of defiance, arguing, anger, and refusal to comply with authority figures, without serious aggression or rule-breaking.

Buddy Insight

CMS-HCC V28

N/A

—

Not risk-adjusted for this model/period.

Not mapped

CMS-HCC V24

N/A

—

Not risk-adjusted for this model/period.

Not mapped

ACA/HHS

N/A

—

Not risk-adjusted for this model/period.

Not mapped

ESRD/PACE

N/A

—

Not risk-adjusted for this model/period.

Not mapped

RXHCC

Mapped

HCC 133

Personality Disorders, Anxiet...

RAF 0.035

Code Book Path

Official

F91Conduct disorders

F91.3Oppositional defiant disorder

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for F91.3 in this effective period.

Excludes 2

Official

conduct problems associated with attention-deficit hyperactivity disorder (F90.-)
mood [affective] disorders (F30-F39)
pervasive developmental disorders (F84.-)
schizophrenia (F20.-)

Related Child Codes

Official

F91.0Conduct disorder confined to family context

F91.1Conduct disorder, childhood-onset type

F91.2Conduct disorder, adolescent-onset type

F91.8Other conduct disorders

F91.9Conduct disorder, unspecified

Includes

Official

ICD-10-CM does not list Includes notes for F91.3 in this effective period.

Excludes 1

Official

antisocial behavior (Z72.81-)
antisocial personality disorder (F60.2)

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for F91.3 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for F91.3 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for F91.3 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Provider documentation of oppositional defiant disorder diagnosis

Evidence of persistent pattern (at least 6 months) of angry/irritable mood, argumentative/defiant behavior, or vindictiveness

Documentation that the behavior is observed with at least one individual who is not a sibling

Evidence of functional impairment in social, academic, or occupational settings

MEAT Support

HCC Buddy guidance

Provider documentation of oppositional defiant disorder diagnosis

Evidence of persistent pattern (at least 6 months) of angry/irritable mood, argumentative/defiant behavior, or vindictiveness

Documentation that the behavior is observed with at least one individual who is not a sibling

Evidence of functional impairment in social, academic, or occupational settings

Audit Caution

HCC Buddy guidance

Coding ODD when the behavior pattern meets criteria for the more severe conduct disorder — conduct disorder takes precedence

Failing to code comorbid ADHD when it co-occurs with ODD — both should be reported

Diagnosing ODD based on behavior occurring only during mood episodes (depression, mania) — the behavior must be independent

Not distinguishing ODD from normal developmental opposition in toddlers and early preschool age

Common Mistakes

HCC Buddy guidance

F91.1 — Conduct disorder, childhood-onset type; conduct disorder involves more serious violations (aggression, destruction, deceit, theft) beyond defiance

F91.2 — Conduct disorder, adolescent-onset type; same distinction — conduct disorder is more severe

F90.x — ADHD; ADHD frequently co-occurs with ODD but they are separate diagnoses that should be coded independently

F63.81 — Intermittent explosive disorder; IED involves disproportionate aggressive outbursts, not a persistent defiant pattern

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 F91.3 an HCC code?

F91.3 is not in the CMS-HCC V28 or V24 community payment model, but it does map to Personality Disorders, Anxiety, and Other Specified Mental Disorders under the Part D RxHCC model.

Code: F91.3
Description: Oppositional defiant disorder
HCC (V28): No CMS-HCC V28 mapping
RAF: —
Billable: Yes
Payment year: 2026

HCC Category Mapping

RxHCCHCC 133, Personality Disorders, Anxiety, and Other Specified Mental Disorders

0.035

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 F91.3 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for F91.3

For F91.3 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 F91.3 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

F91.3 is the ICD-10-CM diagnosis code for oppositional defiant disorder. A behavioral disorder characterized by a persistent pattern of defiance, arguing, anger, and refusal to comply with authority figures, without serious aggression or rule-breaking. F91.3 sits in the ICD-10-CM chapter for mental, behavioral and neurodevelopmental disorders (f01-f99), within the section covering behavioral and emotional disorders with onset usually occurring in childhood and adolescence (f90-f98).

F91.3 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 F91.3 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 F91.3 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Distinguish from conduct disorder by confirming absence of serious aggression, property destruction, or violation of others' rights
•Document specific oppositional behaviors such as arguing, defiance, and anger outbursts

Clinical Significance

Oppositional defiant disorder (ODD) is characterized by a frequent and persistent pattern of angry/irritable mood, argumentative/defiant behavior, or vindictiveness toward authority figures lasting at least 6 months. ODD is one of the most common childhood behavioral disorders, frequently co-occurring with ADHD, and may progress to conduct disorder. Early intervention with behavioral therapy and parent training is effective in many cases.

Documentation Requirements

✓Provider documentation of oppositional defiant disorder diagnosis
✓Evidence of persistent pattern (at least 6 months) of angry/irritable mood, argumentative/defiant behavior, or vindictiveness
✓Documentation that the behavior is observed with at least one individual who is not a sibling
✓Evidence of functional impairment in social, academic, or occupational settings
✓Assessment for comorbid ADHD and treatment plan including behavioral interventions

Commonly Confused Codes

•F91.1: Conduct disorder, childhood-onset type; conduct disorder involves more serious violations (aggression, destruction, deceit, theft) beyond defiance
•F91.2: Conduct disorder, adolescent-onset type; same distinction: conduct disorder is more severe
•F90.x: ADHD; ADHD frequently co-occurs with ODD but they are separate diagnoses that should be coded independently
•F63.81: Intermittent explosive disorder; IED involves disproportionate aggressive outbursts, not a persistent defiant pattern