F18.929
BillableInhalant use, unspecified with intoxication, unspecified
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is F18.929 an HCC code?
Yes. F18.929 maps to Drug Use Disorder/Substance Use Disorder, Moderate/Severe under the CMS-HCC V28 risk adjustment model (and Drug/Alcohol Dependence under V24).
HCC Category Mapping
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 F18.929
For F18.929 to 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 F18.929 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
F18.929 is the ICD-10-CM diagnosis code for inhalant use, unspecified with intoxication, unspecified. A person using inhalants without dependence who is currently intoxicated, but the severity or specific complications of the intoxication are not specified. F18.929 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, F18.929 maps to Drug Use Disorder/Substance Use Disorder, Moderate/Severe (HCC 137) with a community, non-dual, aged base RAF weight of 0.358. Under the older CMS-HCC V24 model, F18.929 maps to Drug/Alcohol Dependence (HCC 55) with a community, non-dual, aged base RAF weight of 0.334. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
Use only when intoxication is documented but details about delirium or complications are unclear. Because F18.929 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. 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, RAF weights, and MEAT documentation criteria for F18.929 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use only when intoxication is documented but details about delirium or complications are unclear
- •Seek clarification on whether delirium is present to use more specific F18.921 code
Clinical Significance
This code captures inhalant intoxication where the severity and specific complications are not documented. Even unspecified intoxication indicates active substance use requiring clinical assessment and potential intervention. Coders should query for more specificity when possible, as the complication level affects HCC mapping.
Documentation Requirements
- ✓Provider documentation of inhalant use, specifying the type of inhalant when known (e.g., toluene, gasoline, aerosol propellants, nitrites)
- ✓Documentation of substance use pattern; query provider to determine if abuse or dependence criteria are met for more specific coding
- ✓Documentation of acute intoxication state with signs and symptoms present at the time of encounter
- ✓Assessment and plan addressing the substance use disorder with treatment approach documented
Commonly Confused Codes
- •F18.10-F18.19 (Inhalant abuse codes) — use when documentation supports a pattern of harmful use without dependence
- •F18.20-F18.29 (Inhalant dependence codes) — use when documentation supports physiological or psychological dependence
- •F19.x codes (Other psychoactive substance use) — F19 is for substances other than inhalants; use F18 specifically when the substance is an inhalant