F18.29
BillableInhalant dependence with unspecified inhalant-induced disorder
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is F18.29 an HCC code?
Yes. F18.29 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 F18.29
For F18.29 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 F18.29 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
F18.29 is the ICD-10-CM diagnosis code for inhalant dependence with unspecified inhalant-induced disorder. A person dependent on inhalants with an unspecified mental or physical health problem caused by their inhalant use. F18.29 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, F18.29 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, F18.29 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.
This is a less specific code; use only when the specific inhalant-induced disorder cannot be determined. Because F18.29 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 F18.29 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This is a less specific code; use only when the specific inhalant-induced disorder cannot be determined
- •Attempt to obtain clarification on the type of disorder before defaulting to this unspecified code
Clinical Significance
This code captures an unspecified substance-induced disorder from inhalant dependence, where the specific nature of the complication is not documented. While less specific codes should be avoided when possible, this code still reflects that the substance use is causing identifiable clinical complications. Querying for additional specificity is recommended to support optimal risk adjustment.
Documentation Requirements
- ✓Provider documentation of inhalant use, specifying the type of inhalant when known (e.g., toluene, gasoline, aerosol propellants, nitrites)
- ✓Clinical documentation supporting dependence criteria: tolerance, withdrawal symptoms, compulsive use despite harm, or inability to control use
- ✓Assessment and plan addressing the substance use disorder with treatment approach documented
Commonly Confused Codes
- •F18.10 (Inhalant abuse, uncomplicated) — abuse indicates a less severe use pattern without meeting full dependence criteria; dependence requires documented tolerance, withdrawal, or compulsive use
- •F18.920-F18.99 (Inhalant use, unspecified) — use when the pattern of use (abuse vs. dependence) is not documented; dependence codes require explicit documentation of dependence
- •F19.x codes (Other psychoactive substance use) — F19 is for substances other than inhalants; use F18 specifically when the substance is an inhalant