What is ICD-10 code F45.1?

F45.1 is the ICD-10-CM diagnosis code for Undifferentiated somatoform disorder. A condition where a person experiences multiple physical symptoms across different body systems that cannot be fully explained by medical tests or physical examination, causing significant distress. F45.1 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. F45.1 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. F45.1 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. F45.1 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 F45.1?

F45.1 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 F45.1 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 F45.1?

Document that symptoms are not better explained by another medical or mental health condition Ensure symptoms have persisted for at least 6 months to meet diagnostic criteria

F45.1: Undifferentiated somatoform disorder —

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupF45.1Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Mental, Behavioral and Neurodevelopmental disorders (F01-F99) / Anxiety, dissociative, stress-related, somatoform and other nonpsychotic mental disorders (F40-F48)

F45.1

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

Undifferentiated somatoform disorder

A condition where a person experiences multiple physical symptoms across different body systems that cannot be fully explained by medical tests or physical examination, causing significant distress.

Buddy Insight

Undifferentiated somatoform disorder represents a milder or less extensive presentation than full somatization disorder, with one or more unexplained physical complaints lasting at least six months.

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 133

Personality Disorders, Anxiet...

RAF 0.0

Code Trumping

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Code Book Path

Official

F45Somatoform disorders

F45.1Undifferentiated somatoform disorder

Inclusion Terms

Official

Somatic symptom disorder
Undifferentiated psychosomatic disorder

Excludes 2

Official

dissociative and conversion disorders (F44.-)
factitious disorders (F68.1-, F68.A)
hair-plucking (F63.3)
lalling (F80.0)
lisping (F80.0)

Related Child Codes

Official

F45.0Somatization disorder

F45.2Hypochondriacal disorders

F45.4Pain disorders related to psychological factors

F45.8Other somatoform disorders

F45.9Somatoform disorder, unspecified

Includes

Official

ICD-10-CM does not list Includes notes for F45.1 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for F45.1 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for F45.1 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for F45.1 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for F45.1 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

One or more unexplained somatic complaints persisting for at least six months

Documentation that symptoms are not fully explained by a known medical condition

Evidence that the presentation does not meet full criteria for somatization disorder (F45.0)

Functional impairment or distress related to the somatic complaints

MEAT Support

HCC Buddy guidance

One or more unexplained somatic complaints persisting for at least six months

Documentation that symptoms are not fully explained by a known medical condition

Evidence that the presentation does not meet full criteria for somatization disorder (F45.0)

Functional impairment or distress related to the somatic complaints

Audit Caution

HCC Buddy guidance

Coding undifferentiated somatoform disorder when documentation supports full somatization disorder criteria

Assigning this code for every unexplained symptom without provider documentation of a somatoform etiology

Confusing with functional somatic syndromes like fibromyalgia or irritable bowel syndrome which have their own codes

Using this code before adequate medical workup has ruled out organic disease

Common Mistakes

HCC Buddy guidance

F45.0 (Somatization disorder) — requires more extensive multi-system symptoms beginning before age 30

F45.9 (Somatoform disorder, unspecified) — use F45.1 when undifferentiated type is specifically documented

R68.89 (Other general symptoms and signs) — use somatoform code when psychological etiology is documented

F45.8 (Other somatoform disorders) — use for specified types like psychogenic dysmenorrhea or pruritus

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 F45.1 an HCC code?

No. F45.1 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 133, Personality Disorders, Anxiety, and Other Specified Mental Disorders

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.

MEAT Criteria for F45.1

For F45.1to 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 F45.1 during that encounter, not just copy-forwarded from a problem list.

What This Code Means

F45.1 is the ICD-10-CM diagnosis code for undifferentiated somatoform disorder. A condition where a person experiences multiple physical symptoms across different body systems that cannot be fully explained by medical tests or physical examination, causing significant distress. F45.1 sits in the ICD-10-CM chapter for mental, behavioral and neurodevelopmental disorders (f01-f99), within the section covering anxiety, dissociative, stress-related, somatoform and other nonpsychotic mental disorders (f40-f48).

F45.1 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.

F45.1 maps to RxHCC 133 with a RAF weight of 0.000. It does not map to any CMS-HCC in V28, V24, or ESRD models. The risk adjustment impact is negligible, but accurate coding supports clinical care patterns and behavioral health integration.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for F45.1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Document that symptoms are not better explained by another medical or mental health condition
•Ensure symptoms have persisted for at least 6 months to meet diagnostic criteria

Clinical Significance

Undifferentiated somatoform disorder represents a milder or less extensive presentation than full somatization disorder, with one or more unexplained physical complaints lasting at least six months. This condition is common in primary care settings and helps explain persistent symptoms that elude medical diagnosis. Coding it accurately enables targeted behavioral health interventions.

Documentation Requirements

✓One or more unexplained somatic complaints persisting for at least six months
✓Documentation that symptoms are not fully explained by a known medical condition
✓Evidence that the presentation does not meet full criteria for somatization disorder (F45.0)
✓Functional impairment or distress related to the somatic complaints
✓Medical workup results showing no adequate organic explanation

Commonly Confused Codes

•F45.0 (Somatization disorder): requires more extensive multi-system symptoms beginning before age 30
•F45.9 (Somatoform disorder, unspecified): use F45.1 when undifferentiated type is specifically documented
•R68.89 (Other general symptoms and signs): use somatoform code when psychological etiology is documented
•F45.8 (Other somatoform disorders): use for specified types like psychogenic dysmenorrhea or pruritus
•F44.9 (Dissociative disorder, unspecified): dissociative and somatoform are distinct categories