F15.921
BillableOther stimulant use, unspecified with intoxication delirium
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is F15.921 an HCC code?
Yes. F15.921 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 F15.921
For F15.921 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 F15.921 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
F15.921 is the ICD-10-CM diagnosis code for other stimulant use, unspecified with intoxication delirium. A person using stimulant drugs who is currently intoxicated and experiencing delirium, a state of confusion and disorientation caused by the acute drug effects. F15.921 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, F15.921 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, F15.921 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.
Document specific delirium symptoms (confusion, disorientation, altered consciousness) to justify this more severe code. Because F15.921 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 F15.921 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Document specific delirium symptoms (confusion, disorientation, altered consciousness) to justify this more severe code
- •Consider monitoring for medical complications and safety risks associated with stimulant-induced delirium
Clinical Significance
Stimulant use, unspecified with intoxication delirium is a high-acuity presentation requiring emergency medical management. Delirium during stimulant intoxication indicates severe neuropsychiatric toxicity with altered consciousness, confusion, and potential for life-threatening complications including hyperthermia and cardiovascular collapse. This code is commonly used in acute care settings where the use pattern is not yet characterized.
Documentation Requirements
- ✓Documentation of stimulant use
- ✓Clinical evidence of acute intoxication
- ✓Specific documentation of delirium: acute confusion, altered consciousness, disorientation
- ✓Vital signs and laboratory findings (elevated temperature, heart rate, CK levels)
- ✓Emergency interventions performed and level of care provided