Q92.0
BillableWhole chromosome trisomy, nonmosaicism (meiotic nondisjunction)
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is Q92.0 an HCC code?
No. Q92.0 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 Q92.0
For Q92.0to 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 Q92.0 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
Q92.0 is the ICD-10-CM diagnosis code for whole chromosome trisomy, nonmosaicism (meiotic nondisjunction). A chromosomal condition where an entire extra chromosome is present in all cells due to meiotic nondisjunction; the specific chromosome involved should be identified for complete coding. Q92.0 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).
Q92.0 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.
Maps to RxHCC 148 (Mild Intellectual Disabilities) with RAF weight 0.0 in the RxHCC model only. The condition does not contribute to CMS-HCC risk adjustment despite potential for significant developmental and medical complexity. Coders reviewing Q92.0 should check whether additional documentation would support a more specific child code in the same hierarchy that does map to a payment HCC — capturing the correct specificity is the highest-leverage RAF improvement available within accurate coding.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for Q92.0 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This is a parent code; identify which chromosome is involved (e.g., trisomy 21, 18, 13) and use the most specific code available
- •Meiotic nondisjunction indicates the error occurred during parental meiosis, which is important for genetic counseling
Clinical Significance
Whole chromosome trisomy from meiotic nondisjunction indicates a complete extra chromosome in all cells, typically associated with more severe phenotypic effects than mosaic forms. The specific chromosome involved determines prognosis and management needs, making identification crucial for care planning.
Documentation Requirements
- ✓Karyotype analysis showing complete trisomy
- ✓Documentation of meiotic nondisjunction mechanism
- ✓Identification of the specific chromosome involved
- ✓Clinical phenotype assessment
- ✓Developmental evaluation findings
- ✓Associated medical complications
- ✓Growth and developmental milestones
- ✓Genetic counseling documentation