Q23.0 vs Q24.4
Q23.0 and Q24.4 can never be reported together. ICD-10-CM declares them mutually exclusive with an Excludes1 note, meaning the two conditions cannot occur in the same patient — so exactly one of them is correct for any given encounter.
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
- Stenosis, stenotic › aortic › congenital (cicatricial)
- Stenosis, stenotic › valve › congenital › aortic (cicatricial)
- 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 (cicatricial)
- Stricture › subaortic
- Anomaly, anomalous › heart › valve NEC › aortic › stenosis › subaortic (congenital) (unspecified type)
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