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F31.9 ICD-10-CM Code: Bipolar disorder, unspecified

F31.9 maps to CMS-HCC V28 154. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC Buddy coding tools

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 lookupF31.9

FY 2026 Apr update / Mental, Behavioral and Neurodevelopmental disorders (F01-F99) / Mood [affective] disorders (F30-F39)

F31.9

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

Bipolar disorder, unspecified

Bipolar disorder diagnosed but without enough information to specify the type, severity, or current episode status.

Buddy the Bee presenting code insight

Buddy Insight

Bipolar disorder, unspecified is used when the provider documents a bipolar diagnosis but does not specify the type (I vs II), current episode (manic, depressed, mixed), or remission status.

OverviewRisk ModelsCode BookDocumentationAuditNotesEdition comparison

CMS-HCC V28

HCC 154

Coefficient HCC 154: 0.351 (Community Non-Dual Aged (CNA))

CMS-HCC V24

Historical

Historical

Not used for CY2026 payment

ACA/HHS

Context needed

HCC 088

Coefficient needs member context

ESRD/PACE

Context needed

HCC 59

Coefficient needs member context

RXHCC

HCC 131

Code-level coefficient reference

Code Book Path

Official
F31Bipolar disorderF31.9Bipolar disorder, unspecified

Inclusion Terms

Official
  • Manic depression

Excludes 2

Official
  • symptoms, signs and abnormal clinical laboratory findings, not elsewhere classified (R00-R99)Inherited from F01-F99, F31
  • cyclothymia (F34.0)Inherited from F01-F99, F31

Related Codes

Official
F31.0Bipolar disorder, current episode hypomanicF31.1Bipolar disorder, current episode manic without psychotic featuresF31.2Bipolar disorder, current episode manic severe with psychotic featuresF31.3Bipolar disorder, current episode depressed, mild or moderate severityF31.4Bipolar disorder, current episode depressed, severe, without psychotic features

Includes

Official
  • disorders of psychological developmentInherited from F01-F99, F31
  • bipolar I disorderInherited from F01-F99, F31
  • bipolar type I disorderInherited from F01-F99, F31
  • manic-depressive illnessInherited from F01-F99, F31
  • manic-depressive psychosisInherited from F01-F99, F31
  • manic-depressive reactionInherited from F01-F99, F31
  • seasonal bipolar disorderInherited from F01-F99, F31

Excludes 1

Official
  • bipolar disorder, single manic episode (F30.-)Inherited from F31
  • major depressive disorder, single episode (F32.-)Inherited from F31
  • major depressive disorder, recurrent (F33.-)Inherited from F31

Code First

Official

No Code First sequencing instructions are included in this display for F31.9. Check the code and parent instructions in the Code Book.

Use Additional

Official

No Use Additional Code instructions are included in this display for F31.9. Check the code and parent instructions in the Code Book.

Code Also

Official

No Code Also instructions are included in this display for F31.9. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance
Provider documentation of bipolar disorder as a diagnosis
Current symptom status or episode type should be queried if not documented
Treatment plan consistent with bipolar disorder management
Medication list supporting the diagnosis (mood stabilizers, atypical antipsychotics)

MEAT Support

HCC Buddy guidance
Provider documentation of bipolar disorder as a diagnosis
Current symptom status or episode type should be queried if not documented
Treatment plan consistent with bipolar disorder management
Medication list supporting the diagnosis (mood stabilizers, atypical antipsychotics)

Audit Caution

HCC Buddy guidance
Using unspecified when the provider has documented episode type, severity, or remission status that allows a more specific code
Not querying the provider for additional specificity — this is one of the most common opportunities for documentation improvement
Confusing bipolar disorder, unspecified with unspecified mood disorder (F39)
Using this code when the provider documents 'mood disorder' without confirming bipolar diagnosis

Common Mistakes

HCC Buddy guidance
F31.81 — Bipolar II disorder: Specific type that should be coded when documented
F31.0-F31.64 — Episode-specific bipolar codes: Use when current episode type and severity are documented
F39 — Unspecified mood disorder: Use when bipolar is not confirmed, only mood disorder
F31.70 — Bipolar disorder, remission: Use when remission is documented even if episode type is unspecified

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 F31.9 an HCC code?

Yes. F31.9 (Bipolar disorder, unspecified) maps to HCC 154, Bipolar Disorders without Psychosis under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.351. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.

Coder answer: F31.9 is billable and maps to V28 HCC 154, Bipolar Disorders without Psychosis. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code
F31.9
Description
Bipolar disorder, unspecified
HCC (V28)
HCC 154 — Bipolar Disorders without Psychosis
RAF reference coefficient
0.351
Billable
Yes
Payment year
2026

HCC Category Mapping

V28HCC 154, Bipolar Disorders without Psychosis
0.351
RxHCCHCC 131, Bipolar Disorders
Not separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. 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 context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work F31.9 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for F31.9

For F31.9, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

  • 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

Coder workflow notes

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What This Code Means

F31.9 is the ICD-10-CM diagnosis code for bipolar disorder, unspecified. Bipolar disorder diagnosed but without enough information to specify the type, severity, or current episode status. F31.9 sits in the ICD-10-CM chapter for mental, behavioral and neurodevelopmental disorders (f01-f99), within the section covering mood [affective] disorders (f30-f39).

Under the CMS-HCC V28 risk adjustment model, F31.9 maps to Bipolar Disorders without Psychosis (HCC 154) with a source-labeled community, non-dual, aged reference coefficient of 0.351. No V24 mapping is shown for F31.9; use the applicable model and payment year when reviewing the V28 mapping. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.

This is a non-specific code; use only when more specific bipolar codes cannot be determined from documentation. For F31.9, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for F31.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •This is a non-specific code; use only when more specific bipolar codes cannot be determined from documentation
  • •Query the provider for additional details to assign a more specific bipolar code

Clinical Significance

Bipolar disorder, unspecified is used when the provider documents a bipolar diagnosis but does not specify the type (I vs II), current episode (manic, depressed, mixed), or remission status. While this code captures the diagnosis for risk adjustment, it represents a documentation improvement opportunity. Querying for specificity improves both clinical care and coding accuracy.

Documentation Requirements

  • ✓Provider documentation of bipolar disorder as a diagnosis
  • ✓Current symptom status or episode type should be queried if not documented
  • ✓Treatment plan consistent with bipolar disorder management
  • ✓Medication list supporting the diagnosis (mood stabilizers, atypical antipsychotics)
  • ✓Provider should be queried for: current episode type, severity, remission status, type I vs II

Commonly Confused Codes

  • •F31.81: Bipolar II disorder: Specific type that should be coded when documented
  • •F31.0-F31.64: Episode-specific bipolar codes: Use when current episode type and severity are documented
  • •F39: Unspecified mood disorder: Use when bipolar is not confirmed, only mood disorder
  • •F31.70: Bipolar disorder, remission: Use when remission is documented even if episode type is unspecified

Child Codes

F31.0Bipolar disorder, current episode hypomanic
HCC 154
F31.1Bipolar disorder, current episode manic without psychotic features
F31.2Bipolar disorder, current episode manic severe with psychotic features
HCC 152
F31.3Bipolar disorder, current episode depressed, mild or moderate severity
F31.4Bipolar disorder, current episode depressed, severe, without psychotic features
HCC 154
F31.5Bipolar disorder, current episode depressed, severe, with psychotic features
HCC 152
F31.6Bipolar disorder, current episode mixed
F31.7Bipolar disorder, currently in remission
F31.8Other bipolar disorders
F31.9Bipolar disorder, unspecified
HCC 154

Code Hierarchy

└F31Bipolar disorder└F31.9Bipolar disorder, unspecified
└F31.9Bipolar disorder, unspecified

Also searched as

  • bipolar
  • BPAD
  • bipolar disorder
  • F31 9
  • F319

For F31.9, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

F31.9 maps to CMS-HCC V28 category 154, Bipolar Disorders without Psychosis. See the ICD-10 to HCC mapping hub for how the V28 crosswalk works. The mapping identifies a payment HCC category for F31.9. Review its source-labeled HCC coefficient above, check the RAF Calculator with complete member context for CMS-HCC V28 PY2026, and confirm the documentation the chart needs before the code is submitted. HCC Buddy shows no RAF score unless every required source and calculation check passes.

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