Q21.12 ICD-10-CM Code: Patent foramen ovale
Q21.12 is not a CMS-HCC payment code. MEAT criteria · RAF Calculator · HCC coding software
HCC Buddy Code Card
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FY 2026 Apr update / Congenital malformations, deformations and chromosomal abnormalities (Q00-QA0) / Congenital malformations of the circulatory system (Q20-Q28)
Q21.12
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidancePatent 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.
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
HistoricalHistorical
Not used for CY2026 payment
ACA/HHS
MappedHCC 139
Code-level coefficient reference
ESRD/PACE
N/A—
Not mapped
RXHCC
N/A—
Not mapped
Code Book Path
Inclusion Terms
Official- Persistent foramen ovale
Excludes 2
Official- inborn errors of metabolism (E70-E88)Inherited from Q00-QA0, Q21.1
- ostium primum atrial septal defect (type I) (Q21.20)Inherited from Q00-QA0, Q21.1
Related Codes
Includes
OfficialNo Includes notes are included in this display for Q21.12. Check the code and parent instructions in the Code Book.
Excludes 1
Official- acquired cardiac septal defect (I51.0)Inherited from Q21
Code First
OfficialNo Code First sequencing instructions are included in this display for Q21.12. Check the code and parent instructions in the Code Book.
Use Additional
OfficialNo Use Additional Code instructions are included in this display for Q21.12. Check the code and parent instructions in the Code Book.
Code Also
OfficialNo Code Also instructions are included in this display for Q21.12. Check the code and parent instructions in the Code Book.
Buddy Documentation Tip
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is Q21.12 an HCC code?
Q21.12 has no mapping under the current CMS-HCC V28 community payment model. Q21.12 also appears in the HHS-HCC commercial risk model (HCC 139 (HHS-HCC 139 adult, RAF varies by metal level)), which is a commercial market model rather than a Medicare Advantage payment mapping.
- Code
- Q21.12
- Description
- Patent foramen ovale
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF reference coefficient
- —
- Billable
- Yes
- Payment year
- 2026
Coder workflow notes
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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 and chromosomal abnormalities (q00-qa0), within the section covering congenital malformations of the circulatory system (q20-q28).
Q21.12 has no mapping under the current CMS-HCC V28 community payment model. Q21.12 also appears in the HHS-HCC commercial risk model (HCC 139 (HHS-HCC 139 adult, RAF varies by metal level)), which is a commercial market model rather than a Medicare Advantage payment mapping. Do not assign V28 risk adjustment value from this page; verify the applicable model and payment year before using this code for risk adjustment.
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, source-labeled coefficient references, 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