Q93.3
BillableDeletion of short arm of chromosome 4
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is Q93.3 an HCC code?
No. Q93.3 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 Q93.3
For Q93.3to 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 Q93.3 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
Q93.3 is the ICD-10-CM diagnosis code for deletion of short arm of chromosome 4. A congenital condition where a portion of the short arm (p arm) of chromosome 4 is missing, which can cause developmental delays, intellectual disability, and various physical abnormalities. Q93.3 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).
Q93.3 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. While it doesn't contribute to risk adjustment scoring, it identifies patients with Wolf-Hirschhorn syndrome who typically require multiple medications including anticonvulsants, nutritional supplements, and medications for associated medical conditions.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for Q93.3 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Wolf-Hirschhorn syndrome is the classic presentation of 4p deletion; verify if this specific diagnosis is documented
- •Document the extent of deletion (partial vs. complete) and associated clinical manifestations for comprehensive coding
Clinical Significance
Deletion of the short arm of chromosome 4 (4p- syndrome or Wolf-Hirschhorn syndrome) is a severe chromosomal disorder characterized by distinctive facial features, severe intellectual disability, seizures, and multiple congenital anomalies. This condition requires comprehensive medical management including seizure control, developmental support, and monitoring for associated complications.
Documentation Requirements
- ✓Cytogenetic analysis showing 4p deletion
- ✓Size and location of deletion if specified
- ✓Characteristic facial features documented
- ✓Intellectual disability assessment
- ✓Seizure history and management
- ✓Growth parameters and feeding difficulties
- ✓Associated congenital anomalies
- ✓Genetic counseling documentation