Q86.1
BillableFetal hydantoin syndrome
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is Q86.1 an HCC code?
No. Q86.1 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
Q86.1 is the ICD-10-CM diagnosis code for fetal hydantoin syndrome. Fetal hydantoin syndrome is a pattern of birth defects that occurs when a pregnant woman takes hydantoin medications (such as phenytoin for seizures), causing facial and developmental abnormalities in the baby. Q86.1 sits in the ICD-10-CM chapter for congenital malformations, deformations, chromosomal abnormalities, and genetic disorders (q00-qa0), within the section covering other congenital malformations (q80-q89).
Q86.1 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.
Document the specific hydantoin medication used during pregnancy in the clinical record.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for Q86.1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Document the specific hydantoin medication used during pregnancy in the clinical record
- •Link this diagnosis to maternal medication use during pregnancy for complete clinical documentation