F15.121
BillableOther stimulant abuse with intoxication delirium
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is F15.121 an HCC code?
Yes. F15.121 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 F15.121
For F15.121 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 F15.121 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
F15.121 is the ICD-10-CM diagnosis code for other stimulant abuse with intoxication delirium. Abuse of stimulant drugs other than cocaine with intoxication that includes delirium, a state of confusion and altered mental status. F15.121 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, F15.121 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, F15.121 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.
Delirium is a serious complication; document specific symptoms such as confusion, disorientation, or hallucinations. Because F15.121 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 F15.121 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Delirium is a serious complication; document specific symptoms such as confusion, disorientation, or hallucinations
- •This may require emergency intervention; ensure appropriate level of care is documented
Clinical Significance
Other stimulant abuse with intoxication delirium represents a medical emergency where a patient abusing non-cocaine stimulants develops acute delirium during intoxication. Stimulant-induced delirium can present as excited delirium syndrome with extreme agitation, hyperthermia, superhuman strength, and autonomic instability. Methamphetamine-induced delirium is particularly dangerous due to the drug's long duration of action. This condition carries significant mortality risk and requires emergency medical intervention including sedation, cooling measures, and cardiac monitoring.
Documentation Requirements
- ✓Provider documentation of stimulant abuse (not dependence)
- ✓Documentation of acute delirium with specific features (confusion, disorientation, altered consciousness, agitation)
- ✓Temporal relationship between stimulant use and delirium onset
- ✓Identification of the specific stimulant when possible
- ✓Vital signs including temperature (hyperthermia assessment)
- ✓Medical workup ruling out other causes of delirium
- ✓Level of care and interventions provided
- ✓Laboratory assessment (creatine kinase for rhabdomyolysis, metabolic panel)