DxCodebookFY2027 · Oct 1, 2026 – Sep 30, 2027

Category · FY2027

Q23 Congenital malformations of aortic and mitral valves

  • Header · not billable

Q23 is not billable. The category heads 9 billable codes in FY2027, grouped under 7 subdivisions.

Index → code

  • Parachute mitral valve → Q23.2
  • Quadricuspid aortic valve → Q23.88
  • Bicuspid aortic valve (at birth) (congenital) → Q23.81

Where it sits

  1. Chapter 17 Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders (Q00-QA1)
  2. Q20-Q28 Congenital malformations of the circulatory system (Q20-Q28)
  3. Q23 Congenital malformations of aortic and mitral valves
Billable codes
9
Subdivisions
7
CC / MCC codes
4 / 1
HCC V28 codes
0
New FY2027
0
Index entries
53

Codes in Q23

  1. Q23.0
    Congenital stenosis of aortic valve
    BillableCCExempt
    Inclusion terms 2, Excludes1 3

    Inclusion terms

    • Congenital aortic atresia
    • Congenital aortic stenosis NOS

    Excludes1

    • congenital stenosis of aortic valve in hypoplastic left heart syndrome (Q23.4) Q23.4
    • congenital subaortic stenosis (Q24.4) Q24.4
    • supravalvular aortic stenosis (congenital) (Q25.3) Q25.3
  2. Q23.1
    Congenital insufficiency of aortic valve
    BillableCCExempt
    Inclusion terms 1

    Inclusion terms

    • Congenital aortic insufficiency
  3. Q23.2
    Congenital mitral stenosis
    BillableCCExempt
    Inclusion terms 1

    Inclusion terms

    • Congenital mitral atresia
  4. Q23.3
    Congenital mitral insufficiency
    BillableCCExempt
  5. Q23.4
    Hypoplastic left heart syndrome
    BillableMCCExempt
  6. Q23.8
    Other congenital malformations of aortic and mitral valves
    Header
  7. Q23.81
    Bicuspid aortic valve
    BillableExempt
    Inclusion terms 2, Code also 4

    Inclusion terms

    • Congenital bicuspid aortic valve
    • Unicuspid (congenital) aortic valve (at birth)

    Code also

    • , if applicable, acquired aortic valve disorders, such as:
    • aortic (valve) insufficiency (nonrheumatic) (I35.1) I35.1
    • aortic (valve) stenosis (nonrheumatic) (I35.0) I35.0
    • aortic (valve) stenosis with insufficiency (nonrheumatic) (I35.2) I35.2
  8. Q23.82
    Congenital mitral valve cleft leaflet
    BillableExempt
    Inclusion terms 1

    Inclusion terms

    • Cleft mitral valve leaflet at birth
  9. Q23.88
    Other congenital malformations of aortic and mitral valves
    BillableExempt
  10. Q23.9
    Congenital malformation of aortic and mitral valves, unspecified
    BillableExempt

CC/MCC: as a secondary diagnosis, unless the principal diagnosis is on the code’s PDX exclusion list (MS-DRG v44 Appendix C; list on the code card).

Sources of each column.

Instructions

Notes that also apply

Chapter 17 instructions (Notes 1, Excludes2 1): printed on the chapter 17 page.

Index entries

  • Duroziez's disease (congenital mitral stenosis) → Q23.2
  • Parachute mitral valve → Q23.2
  • Bicuspid aortic valve (at birth) (congenital) → Q23.81
  • Unicuspid aortic valve (at birth) (congenital) → Q23.81
  • Quadricuspid aortic valve → Q23.88
  • Atresia, atreticaortic (orifice) (valve) → Q23.0
  • Atresia, atreticmitral valve → Q23.2
  • Disease, diseasedDuroziez's (congenital mitral stenosis) → Q23.2
  • Fusion, fused (congenital)commissure, mitral valve → Q23.2
  • Supernumerary (congenital)mitral cusps → Q23.2
  • Hypoplasia, hypoplasticleft heart syndrome → Q23.4
  • Syndromehypoplastic left-heart → Q23.4
  • Cleft (congenital)mitral valve leaflet (at birth) (congenital) → Q23.82
  • Supernumerary (congenital)aortic cusps → Q23.88
  • Anomaly, anomalous (congenital) (unspecified type)aortic cusp or valve → Q23.9
  • Anomaly, anomalous (congenital) (unspecified type)mitral (leaflets) (valve) → Q23.9
  • Malformation (congenital)aortic valve → Q23.9
  • Malformation (congenital)mitral valve → Q23.9
  • Stenosis, stenotic (cicatricial)aortic (valve)congenital → Q23.0
  • Hypoplasia, hypoplasticaorta, aorticvalve → Q23.1
  • Insufficiency, insufficientaortic (valve)congenital → Q23.1
  • Anomaly, anomalous (congenital) (unspecified type)mitral (leaflets) (valve)stenosis → Q23.2
  • Deformitymitral (leaflets) (valve)parachute → Q23.2
  • Deformitymitral (leaflets) (valve)stenosis, congenital → Q23.2
  • Fusion, fused (congenital)cusps, heart valve NECmitral → Q23.2
  • Stenosis, stenotic (cicatricial)mitral (chronic) (inactive) (valve)congenital → Q23.2
  • Supernumerary (congenital)cusps, heart valve NECmitral → Q23.2
  • Anomaly, anomalous (congenital) (unspecified type)mitral (leaflets) (valve)insufficiency → Q23.3
  • Insufficiency, insufficientmitral (valve)congenital → Q23.3
  • Regurgitationmitral (valve)congenital → Q23.3
  • Atresia, atreticaortic (orifice) (valve)congenital with hypoplasia of ascending aorta and defective development of left ventricle (with mitral stenosis) → Q23.4
  • Atresia, atreticaortic (orifice) (valve)in hypoplastic left heart syndrome → Q23.4
  • Atresia, atreticmitral valvein hypoplastic left heart syndrome → Q23.4
  • Hypoplasia, hypoplasticaorta, aorticascending, in hypoplastic left heart syndrome → Q23.4
  • Anomaly, anomalous (congenital) (unspecified type)mitral (leaflets) (valve)cleft → Q23.82
  • Anomaly, anomalous (congenital) (unspecified type)mitral (leaflets) (valve)specified NEC → Q23.88
  • Deformityaorticcusp or valve (congenital) → Q23.88
  • Malformation (congenital)aortic valvespecified NEC → Q23.88
  • Malformation (congenital)mitral valvespecified NEC → Q23.88
  • Supernumerary (congenital)cusps, heart valve NECaortic → Q23.88

13 more, longer entries are not listed; the search box finds them by word.

NCHS Alphabetic Index. Index first, then the Tabular List.

Hierarchy