Q21.12
BillablePatent foramen ovale
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is Q21.12 an HCC code?
No. Q21.12 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
Q21.12 is the ICD-10-CM diagnosis code for patent foramen ovale. A small opening in the wall between the two upper chambers of the heart that normally closes after birth but remains open, allowing a small amount of blood to pass through. Q21.12 sits in the ICD-10-CM chapter for congenital malformations, deformations, chromosomal abnormalities, and genetic disorders (q00-qa0), within the section covering congenital malformations of the circulatory system (q20-q28).
Q21.12 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.
Patent foramen ovale (PFO) is extremely common and often clinically insignificant; code only when documented as a diagnosis.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for Q21.12 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Patent foramen ovale (PFO) is extremely common and often clinically insignificant; code only when documented as a diagnosis
- •Document whether the PFO is associated with symptoms or other cardiac conditions that warrant treatment