F18.129
BillableInhalant abuse with intoxication, unspecified
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is F18.129 an HCC code?
Yes. F18.129 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 F18.129
For F18.129 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 F18.129 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
F18.129 is the ICD-10-CM diagnosis code for inhalant abuse with intoxication, unspecified. A person is abusing inhalants with intoxication, but the specific details or complications of the intoxication are not specified. F18.129 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, F18.129 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, F18.129 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 this code only when intoxication is documented but the coder cannot determine if it is complicated or uncomplicated. Because F18.129 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 F18.129 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use this code only when intoxication is documented but the coder cannot determine if it is complicated or uncomplicated
- •Query the provider for clarification on whether delirium or other complications are present
Clinical Significance
Inhalant abuse with unspecified intoxication indicates documentation gaps regarding whether delirium or complications are present during intoxication. Given the life-threatening nature of inhalant intoxication, the lack of specificity is a clinical concern that should prompt provider queries.
Documentation Requirements
- ✓Documentation of inhalant abuse with intoxication
- ✓Provider query for delirium presence or absence
- ✓Available clinical signs of intoxication
- ✓Vital signs and monitoring data
- ✓Reason specificity cannot be determined
Commonly Confused Codes
- •F18.120 — With uncomplicated intoxication; preferred when delirium is ruled out
- •F18.121 — With intoxication delirium; preferred when delirium is documented
- •F18.10 — Inhalant abuse, uncomplicated; use when no intoxication is occurring
- •F18.229 — Inhalant dependence with intoxication, unspecified; use when dependence is documented