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F09 ICD-10-CM Code: Unspecified mental disorder due to known physiological condition

F09 is not a CMS-HCC payment code. MEAT criteria · RAF Calculator · free HCC coding tools

ICD-10-CM Code View

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FY 2026 Apr update / Mental, Behavioral and Neurodevelopmental disorders (F01-F99) / Mental disorders due to known physiological conditions (F01-F09)

F09

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

Unspecified mental disorder due to known physiological condition

A mental health disorder caused by a known medical condition when the specific type of mental disorder cannot be determined or is not specified.

CMS-HCC V28

N/A

—

Not mapped

CMS-HCC V24

Historical

Historical

Not used for CY2026 payment

ACA/HHS

N/A

—

Not mapped

ESRD/PACE

N/A

—

Not mapped

RXHCC

N/A

—

Not mapped

Code Book Path

Official
F0Mental disorders due to known physiological conditions (F01-F09)
F09Unspecified mental disorder due to known physiological condition

Inclusion Terms

Official
  • Mental disorder NOS due to known physiological condition
  • Organic brain syndrome NOS
  • Organic mental disorder NOS
  • Organic psychosis NOS
  • Symptomatic psychosis NOS

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for F09 in this effective period.

Related Child Codes

Official

ICD-10-CM does not list child codes under F09 for this display context.

Includes

Official

ICD-10-CM does not list Includes notes for F09 in this effective period.

Excludes 1

Official
  • mild neurocognitive disorder due to known physiological condition (F06.7-)
  • psychosis NOS (F29)

Code First

Official
  • the underlying physiological condition

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for F09 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for F09 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance
This is a catch-all code for mental disorders due to medical conditions that don't fit other specific categories
Document the underlying medical condition and attempt to specify the mental disorder type when possible

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 F09 an HCC code?

No. F09 is a billable ICD-10-CM code with no mapping under the CMS-HCC V28 or V24 community payment models, and none under the ESRD, Part D RxHCC, or HHS-HCC models.

Code
F09
Description
Unspecified mental disorder due to known physiological condition
HCC (V28)
No CMS-HCC V28 mapping
RAF reference coefficient
—
Billable
Yes
Payment year
2026

Coder workflow notes

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This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).

What This Code Means

F09 is the ICD-10-CM diagnosis code for unspecified mental disorder due to known physiological condition. A mental health disorder caused by a known medical condition when the specific type of mental disorder cannot be determined or is not specified. F09 sits in the ICD-10-CM chapter for mental, behavioral and neurodevelopmental disorders (f01-f99), within the section covering mental disorders due to known physiological conditions (f01-f09).

F09 is a billable ICD-10-CM code, but the current payload does not show a mapping under the CMS-HCC V28 or V24 community payment models, and none under the ESRD, Part D RxHCC, or HHS-HCC models. Do not assign risk adjustment value from this page when no source-backed mapping is shown; verify the applicable model and payment year.

This is a catch-all code for mental disorders due to medical conditions that don't fit other specific categories.

HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for F09 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •This is a catch-all code for mental disorders due to medical conditions that don't fit other specific categories
  • •Document the underlying medical condition and attempt to specify the mental disorder type when possible

Excludes 1, Do NOT code together

  • mild neurocognitive disorder due to known physiological condition (F06.7-)
  • psychosis NOS (F29)

Code First

  • the underlying physiological condition

Code Hierarchy

└F09Unspecified mental disorder due to known physiological condition
└F09Unspecified mental disorder due to known physiological condition

Work F09 in HCC Buddy

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