Skip to content
Dx

ICD-10-CM 2027 diagnosis code

Q23.0Congenital stenosis of aortic valve

✓ Billable / specificPOA exemptCC — complication/comorbidity

Q23.0 is a valid, billable ICD-10-CM code for congenital stenosis of aortic valve. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Looking up by condition? See ICD-10 code for Aortic atresia.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About Q23.0

Q23.0 is the ICD-10-CM diagnosis code for congenital stenosis of aortic valve. It belongs to category Q23 (congenital malformations of aortic and mitral valves), block Q20-Q28 (congenital malformations of the circulatory system) and chapter 17 (congenital malformations, deformations, chromosomal abnormalities, and genetic disorders). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within Q23 (congenital malformations of aortic and mitral valves), Q23.0 is specifically for congenital stenosis of aortic valve. Related codes cover congenital insufficiency of aortic valve (Q23.1), congenital mitral stenosis (Q23.2), congenital mitral insufficiency (Q23.3), Hypoplastic left heart syndrome (Q23.4), other congenital malformations of aortic and mitral valves (Q23.8) and congenital malformation of aortic and mitral valves, unspecified (Q23.9).

Don't report Q23.0 together with the conditions in its Excludes1 note: congenital stenosis of aortic valve in hypoplastic left heart syndrome (Q23.4), congenital subaortic stenosis (Q24.4) and supravalvular aortic stenosis (congenital) (Q25.3).

As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 306 (Cardiac Congenital and Valvular Disorders with MCC, relative weight 1.546) and DRG 307 (Cardiac Congenital and Valvular Disorders without MCC, relative weight 0.9148), in MDC 05 (Diseases and Disorders of the Circulatory System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It is exempt from present-on-admission (POA) reporting, so no POA indicator is required.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 746.3 (congenital stenosis of aortic valve).

Coding notes

Applicable toConditions and synonyms classified to this code
  • Congenital aortic atresia
  • Congenital aortic stenosis NOS
Excludes1Not coded here — never report together with this code
  • congenital stenosis of aortic valve in hypoplastic left heart syndrome (Q23.4)
  • congenital subaortic stenosis (Q24.4)
  • supravalvular aortic stenosis (congenital) (Q25.3)

Notes that apply from higher levels

Instructions written at a parent level also apply to Q23.0.

Broader instructions also apply from Chapter 17: Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders.

Alphabetic index entries

6 entries

Terms in the official ICD-10-CM index that lead to Q23.0.

Codes whose notes reference Q23.0

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

ICD-9-CM equivalent

Converter →
  • 746.3Congenital stenosis of aortic valveexact

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about Q23.0

Is Q23.0 billable?

Yes. Q23.0 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can Q23.0 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict Q23.0 as a principal diagnosis.

Is Q23.0 a CC or MCC?

Q23.0 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.

What DRG does Q23.0 group to?

Q23.0 is used in the MS-DRG v44.0 logic for MS-DRG 306 (Cardiac Congenital and Valvular Disorders with MCC) and MS-DRG 307 (Cardiac Congenital and Valvular Disorders without MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.

What is the ICD-9 code for Q23.0?

The CMS General Equivalence Mappings map Q23.0 to ICD-9-CM 746.3.