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F18.221 ICD-10-CM Code: Inhalant dependence with intoxication delirium

F18.221 maps to CMS-HCC V28 137. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC coding software

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Code lookupF18.221

FY 2026 Apr update / Mental, Behavioral and Neurodevelopmental disorders (F01-F99) / Mental and behavioral disorders due to psychoactive substance use (F10-F19)

F18.221

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

Inhalant dependence with intoxication delirium

A person who is dependent on inhalants and is currently intoxicated with severe confusion, disorientation, and altered mental status (delirium) as a result.

Buddy the Bee presenting code insight

Buddy Insight

Inhalant dependence with intoxication delirium is a critical medical emergency.

OverviewRisk ModelsCode BookDocumentationAuditNotesEdition comparison

CMS-HCC V28

HCC 137

Coefficient HCC 137: 0.424 (Community Non-Dual Aged (CNA))

CMS-HCC V24

Historical

Historical

Not used for CY2026 payment

ACA/HHS

HCC 082

Code-level coefficient reference

ESRD/PACE

HCC 55

Code-level coefficient reference

RXHCC

N/A

—

Not mapped

Code Book Path

Official
F18.2Inhalant dependenceF18.22Inhalant dependence with intoxicationF18.221Inhalant dependence with intoxication delirium

Inclusion Terms

Official

No inclusion terms are included in this display for F18.221. 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

Related Codes

Official
F18.220Inhalant dependence with intoxication, uncomplicatedF18.229Inhalant dependence with intoxication, unspecified

Includes

Official
  • disorders of psychological developmentInherited from F01-F99, F18
  • volatile solventsInherited from F01-F99, F18

Excludes 1

Official
  • inhalant abuse (F18.1-)Inherited from F18.2
  • inhalant use, unspecified (F18.9-)Inherited from F18.2

Code First

Official

No Code First sequencing instructions are included in this display for F18.221. Check the code and parent instructions in the Code Book.

Use Additional

Official

No Use Additional Code instructions are included in this display for F18.221. Check the code and parent instructions in the Code Book.

Code Also

Official

No Code Also instructions are included in this display for F18.221. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance
Documentation of inhalant dependence
Clinical evidence of delirium: acute confusion, fluctuating consciousness, disorientation
Cardiac monitoring and ECG results
Neurological assessment including GCS

MEAT Support

HCC Buddy guidance
Documentation of inhalant dependence
Clinical evidence of delirium: acute confusion, fluctuating consciousness, disorientation
Cardiac monitoring and ECG results
Neurological assessment including GCS

Audit Caution

HCC Buddy guidance
Coding uncomplicated intoxication when delirium is present
Confusing delirium with psychosis — key difference is level of consciousness
Not documenting specific delirium criteria
Missing concurrent medical emergencies (arrhythmia, seizures) that may need additional coding

Common Mistakes

HCC Buddy guidance
F18.220 — With intoxication, uncomplicated; use when NO delirium is present
F18.229 — With intoxication, unspecified; use only when delirium status unknown
F18.250 — With psychotic disorder with delusions; psychosis maintains consciousness, delirium does not
F18.121 — Inhalant abuse with intoxication delirium; use when abuse rather than dependence

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 F18.221 an HCC code?

Yes. F18.221 (Inhalant dependence with intoxication delirium) maps to HCC 137, Drug Use Disorder, Moderate/Severe, or Drug Use with Non-Psychotic Complications under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.424. 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: F18.221 is billable and maps to V28 HCC 137, Drug Use Disorder, Moderate/Severe, or Drug Use with Non-Psychotic Complications. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code
F18.221
Description
Inhalant dependence with intoxication delirium
HCC (V28)
HCC 137 — Drug Use Disorder, Moderate/Severe, or Drug Use with Non-Psychotic Complications
RAF reference coefficient
0.424
Billable
Yes
Payment year
2026

HCC Category Mapping

V28HCC 137, Drug Use Disorder, Moderate/Severe, or Drug Use with Non-Psychotic Complications
0.424
ESRDHCC 55, Substance Use Disorder/Moderate/Severe/Substance Use with Complications
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 F18.221 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for F18.221

For F18.221, 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

F18.221 is the ICD-10-CM diagnosis code for inhalant dependence with intoxication delirium. A person who is dependent on inhalants and is currently intoxicated with severe confusion, disorientation, and altered mental status (delirium) as a result. F18.221 sits in the ICD-10-CM chapter for mental, behavioral and neurodevelopmental disorders (f01-f99), within the section covering mental and behavioral disorders due to psychoactive substance use (f10-f19).

Under the CMS-HCC V28 risk adjustment model, F18.221 maps to Drug Use Disorder, Moderate/Severe, or Drug Use with Non-Psychotic Complications (HCC 137) with a source-labeled community, non-dual, aged reference coefficient of 0.424. No V24 mapping is shown for F18.221; 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.

Delirium indicates a more severe presentation requiring urgent medical attention. For F18.221, 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 F18.221 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •Delirium indicates a more severe presentation requiring urgent medical attention
  • •Document specific delirium symptoms such as confusion, hallucinations, or disorientation

Clinical Significance

Inhalant dependence with intoxication delirium is a critical medical emergency. The combination of dependence (indicating chronic heavy use) with delirium (altered consciousness) signals severe neurotoxicity and risk of fatal cardiac arrhythmia, seizures, respiratory arrest, or aspiration. Immediate ICU-level care may be required.

Documentation Requirements

  • ✓Documentation of inhalant dependence
  • ✓Clinical evidence of delirium: acute confusion, fluctuating consciousness, disorientation
  • ✓Cardiac monitoring and ECG results
  • ✓Neurological assessment including GCS
  • ✓Type of inhalant when identifiable
  • ✓Emergency interventions and stabilization documented
  • ✓Differential diagnosis ruling out other delirium causes

Commonly Confused Codes

  • •F18.220: With intoxication, uncomplicated; use when NO delirium is present
  • •F18.229: With intoxication, unspecified; use only when delirium status unknown
  • •F18.250: With psychotic disorder with delusions; psychosis maintains consciousness, delirium does not
  • •F18.121: Inhalant abuse with intoxication delirium; use when abuse rather than dependence

Child Codes

F18.220Inhalant dependence with intoxication, uncomplicated
HCC 137
F18.221Inhalant dependence with intoxication delirium
HCC 137
F18.229Inhalant dependence with intoxication, unspecified
HCC 137

Code Hierarchy

└F18Inhalant related disorders└F18.2Inhalant dependence└F18.22Inhalant dependence with intoxication└F18.221Inhalant dependence with intoxication delirium
└F18.221Inhalant dependence with intoxication delirium

Also searched as

  • F18 221
  • F18221

For F18.221, 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.

F18.221 maps to CMS-HCC V28 category 137, Drug Use Disorder, Moderate/Severe, or Drug Use with Non-Psychotic Complications. See the ICD-10 to HCC mapping hub for how the V28 crosswalk works. The mapping identifies a payment HCC category for F18.221. 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.

Work F18.221 in HCC Buddy

Open F18.221 in the Code Book for the full Index-to-Tabular path, MEAT checklist, and V28 HCC mapping, or in the Encoder to code from a keyword search. Pro includes 7 days to try everything, no card required.

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