F18.27
BillableInhalant dependence with inhalant-induced dementia
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is F18.27 an HCC code?
Yes. F18.27 maps to Drug/Alcohol Psychosis under the CMS-HCC V28 risk adjustment model (and Drug/Alcohol Psychosis 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 F18.27
For F18.27 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 F18.27 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
F18.27 is the ICD-10-CM diagnosis code for inhalant dependence with inhalant-induced dementia. A person dependent on inhalants who has developed dementia (permanent memory loss and cognitive decline) caused by their chronic inhalant abuse. F18.27 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, F18.27 maps to Drug/Alcohol Psychosis (HCC 135) with a community, non-dual, aged base RAF weight of 0.000. Under the older V24 model, F18.27 mapped to the same category but with a base RAF weight of 0.434 — V28 recalibrated weights across the entire model. 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.
Document the causal relationship between inhalant dependence and dementia development. Because F18.27 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 F18.27 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Document the causal relationship between inhalant dependence and dementia development
- •This represents permanent cognitive damage from inhalant exposure, not temporary intoxication effects
Clinical Significance
Inhalant dependence with induced dementia is among the most severe inhalant-related diagnoses. Chronic exposure to toluene and other volatile solvents causes progressive white matter destruction, leading to irreversible cognitive decline, memory loss, and functional impairment. These patients require long-term custodial care and intensive medical support.
Documentation Requirements
- ✓Documentation of inhalant dependence
- ✓Formal cognitive assessment demonstrating dementia (MMSE, MoCA, or neuropsychological battery)
- ✓Provider statement linking dementia to chronic inhalant use
- ✓Brain MRI showing white matter changes, cerebellar atrophy, or basal ganglia damage
- ✓Functional assessment documenting impact on daily activities
- ✓Timeline of cognitive decline relative to inhalant use history
- ✓Differentiation from other dementia etiologies