Q92.9
BillableTrisomy and partial trisomy of autosomes, unspecified
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is Q92.9 an HCC code?
No. Q92.9 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
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 Q92.9
For Q92.9to 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 Q92.9 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
Q92.9 is the ICD-10-CM diagnosis code for trisomy and partial trisomy of autosomes, unspecified. A chromosomal condition involving extra copies of whole or partial chromosomes, but the specific type or chromosome involved is not specified or documented. Q92.9 sits in the ICD-10-CM chapter for congenital malformations, deformations, chromosomal abnormalities, and genetic disorders (q00-qa0), within the section covering chromosomal abnormalities, not elsewhere classified (q90-q99).
Q92.9 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
This code maps to RxHCC 148 (Mild Intellectual Disabilities) with a RAF weight of 0.0 in the RxHCC model. Although it doesn't impact risk adjustment scoring, it identifies patients who may need specialized medications for associated conditions like seizures, behavioral disorders, or developmental delays.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for Q92.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
Clinical Significance
This unspecified code represents chromosomal abnormalities involving extra genetic material when the specific type or chromosome cannot be identified. While less specific than other trisomy codes, it still indicates significant chromosomal abnormalities that typically result in developmental delays, intellectual disabilities, and potential medical complications.
Documentation Requirements
- ✓Evidence of chromosomal abnormality with extra genetic material
- ✓Clinical manifestations present in the individual
- ✓Attempts at chromosomal identification documented
- ✓Developmental or intellectual disability assessment
- ✓Associated congenital anomalies if present
- ✓Genetic consultation notes
- ✓Reason why specific trisomy cannot be determined
- ✓Family history of chromosomal abnormalities