F21
BillableSchizotypal disorder
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is F21 an HCC code?
Yes. F21 maps to Personality Disorders and Dissociative Disorders under the CMS-HCC V28 risk adjustment model (and Personality Disorders 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 F21
For F21to 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 F21 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
F21 is the ICD-10-CM diagnosis code for schizotypal disorder. A personality disorder characterized by odd beliefs, unusual perceptual experiences, and eccentric behavior, but without the full psychotic symptoms seen in schizophrenia. F21 sits in the ICD-10-CM chapter for mental, behavioral and neurodevelopmental disorders (f01-f99), within the section covering schizophrenia, schizotypal, delusional, and other non-mood psychotic disorders (f20-f29).
Under the CMS-HCC V28 risk adjustment model, F21 maps to Personality Disorders and Dissociative Disorders (HCC 153) with a community, non-dual, aged base RAF weight of 1.241. Under the older CMS-HCC V24 model, F21 maps to Personality Disorders (HCC 60) with a community, non-dual, aged base RAF weight of 0.000. 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.
Distinguish from schizophrenia by confirming the absence of full psychotic episodes. Because F21 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 F21 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Distinguish from schizophrenia by confirming the absence of full psychotic episodes
- •Document the presence of magical thinking, ideas of reference, or unusual perceptions
Clinical Significance
Schizotypal disorder is a personality disorder characterized by eccentric behavior, odd beliefs (magical thinking), unusual perceptual experiences, and social deficits without the full psychotic symptoms of schizophrenia. It is classified within the schizophrenia spectrum and represents a lifelong pattern of cognitive and interpersonal deficits. The condition requires ongoing mental health treatment and has significant implications for patient functioning and quality of life.
Documentation Requirements
- ✓Documented diagnosis by a qualified mental health professional
- ✓Description of characteristic features (odd beliefs, magical thinking, ideas of reference, unusual perceptual experiences, eccentric behavior, social anxiety)
- ✓Assessment confirming absence of full psychotic episodes (which would suggest schizophrenia)
- ✓Documentation that the pattern is pervasive and longstanding (personality disorder criteria)
- ✓Current functional assessment and treatment plan
- ✓Differentiation from schizophrenia, avoidant personality disorder, and autism spectrum disorders
Excludes 2 — Not included here, may code separately
Commonly Confused Codes
- •F20.0 — Paranoid schizophrenia involves full psychotic episodes with delusions; schizotypal disorder does not
- •F60.1 — Schizoid personality disorder shares social withdrawal but lacks the odd beliefs and perceptual experiences of schizotypal disorder
- •F20.5 — Residual schizophrenia has a history of psychotic episodes; schizotypal disorder does not
- •F84.0 — Autism spectrum disorder may share social deficits but has different core features
- •F60.0 — Paranoid personality disorder involves distrust without the perceptual oddities of schizotypal disorder