FY2027
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Excludes1 pair

Q23.0 vs Q24.4

Q23.0 and Q24.4 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 Q23.0
congenital subaortic stenosis (Q24.4)
Q23.0

Congenital stenosis of aortic valve

Billable
Chapter 17
Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders
Section
Q20-Q28
Use when the record says
  • Congenital aortic atresia
  • Congenital aortic stenosis NOS
Indexed under
  • Atresia, atretic › aortic (orifice) (valve)
  • Stenosis, stenotic › aortic › congenital
  • Stenosis, stenotic › valve › congenital › aortic
  • Stricture › heart › valve › aortic
  • Stricture › valve › congenital › aortic
Q24.4

Congenital subaortic stenosis

Billable
Chapter 17
Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders
Section
Q20-Q28
Indexed under
  • Stenosis, stenotic › subaortic (congenital)
  • Stricture › subaortic
  • Anomaly, anomalous › heart › valve NEC › aortic › stenosis › subaortic

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