FY2027
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Excludes1 pair

Q20.0 vs Q21.4

Q20.0 and Q21.4 are not coded together. ICD-10-CM declares them mutually exclusive with an Excludes1 note — the two conditions are not expected to occur together, so exactly one of them is normally correct for a given encounter. The Official Guidelines carve out one exception: if the two conditions are clearly unrelated to each other, both may be reported.

The official note, declared on Q20.0
aortic septal defect (Q21.4)
Q20.0

Common arterial trunk

Billable
Chapter 17
Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders
Section
Q20-Q28
Use when the record says
  • Persistent truncus arteriosus
Indexed under
  • Common › arterial trunk
  • Common › truncus (arteriosus)
  • Persistence, persistent › truncus arteriosus or communis
  • Truncus › arteriosus (persistent)
  • Truncus › communis
Q21.4

Aortopulmonary septal defect

Billable
Chapter 17
Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders
Section
Q20-Q28
Use when the record says
  • Aortic septal defect
  • Aortopulmonary window
Indexed under
  • Defect, defective › aorticopulmonary septum
  • Fenestration, fenestrated › aortico-pulmonary
  • Window › aorticopulmonary
  • Absence › septum › between aorta and pulmonary artery
  • Agenesis › septum › between aorta and pulmonary artery

Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027