F98.5 ICD-10-CM Code: Adult onset fluency disorder
F98.5 is not a CMS-HCC payment code. MEAT criteria · RAF Calculator · HCC Buddy coding tools
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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)
F98.5
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceAdult onset fluency disorder
A speech fluency disorder beginning in adulthood, such as stuttering or stammering that develops after normal speech development in childhood.
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
HistoricalHistorical
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
Inclusion Terms
OfficialNo inclusion terms are included in this display for F98.5. Check the code and parent instructions in the Code Book.
Excludes 2
Official- symptoms, signs and abnormal clinical laboratory findings, not elsewhere classified (R00-R99)Inherited from F01-F99, F98
- breath-holding spells (R06.89)Inherited from F01-F99, F98
- gender identity disorder of childhood (F64.2)Inherited from F01-F99, F98
- Kleine-Levin syndrome (G47.13)Inherited from F01-F99, F98
- obsessive-compulsive disorder (F42.-)Inherited from F01-F99, F98
- sleep disorders not due to a substance or known physiological condition (F51.-)Inherited from F01-F99, F98
Related Codes
Includes
Official- disorders of psychological developmentInherited from F01-F99
Excludes 1
Official- childhood onset fluency disorder (F80.81)
- dysphasia (R47.02)
- fluency disorder in conditions classified elsewhere (R47.82)
- fluency disorder (stuttering) following cerebrovascular disease (I69. with final characters -23)
- tic disorders (F95.-)
Code First
OfficialNo Code First sequencing instructions are included in this display for F98.5. Check the code and parent instructions in the Code Book.
Use Additional
OfficialNo Use Additional Code instructions are included in this display for F98.5. Check the code and parent instructions in the Code Book.
Code Also
OfficialNo Code Also instructions are included in this display for F98.5. Check the code and parent instructions in the Code Book.
Buddy Documentation Tip
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 F98.5 an HCC code?
No. F98.5 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
- F98.5
- Description
- Adult onset fluency disorder
- 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
F98.5 is the ICD-10-CM diagnosis code for adult onset fluency disorder. A speech fluency disorder beginning in adulthood, such as stuttering or stammering that develops after normal speech development in childhood. F98.5 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).
F98.5 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.
Distinguish this from childhood-onset fluency disorders (F98.81) by documenting that normal fluency was present during childhood.
HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for F98.5 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Distinguish this from childhood-onset fluency disorders (F98.81) by documenting that normal fluency was present during childhood
- •Document the age of onset and any triggering events or associated stressors