2027 ICD-10-CM Diagnosis Code Q23.0Congenital stenosis of aortic valve

ICD-10-CM Codes›Q00-Q99›Q20-Q28›Q23

ICD-10-CM Q23.0
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

Q23.0 is a billable ICD-10-CM diagnosis code for congenital stenosis of aortic valve. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 306 through 307. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 66 closely related codes. The code is exempt from POA reporting. Coders also document this condition as aortic valve calcification. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Cardiac and circulatory congenital anomalies.

Code Identity

ICD-10-CM Code
Q23.0
Billable Status
Yes — Valid for Submission
Code Describes
Congenital stenosis of aortic valve
Short Description
Congenital stenosis of aortic valve
Same as the full description in the CMS dataset.
Parent Code
Q23
Congenital malformations of aortic and mitral valves

Code Classification

ChapterQ00-Q99Congenital malformations, deformations and chromosomal abnormalities
SectionQ20-Q28Congenital malformations of the circulatory system
CategoryQ23Congenital malformations of aortic and mitral valves
This CodeQ23.0Congenital stenosis of aortic valve

Present on Admission (POA)Billing

Q23.0 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review the other POA exempt codes in Congenital malformations of the circulatory system (Q20-Q28).

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Aortic valve calcification
  • Calcific aortic stenosis - bicuspid valve
  • Congenital atresia of aortic valve
  • Congenital critical stenosis of aortic valve with ductus arteriosus dependent systemic circulation
  • Congenital stenosis of aortic valve
  • Critical stenosis of aortic valve
  • Ductus arteriosus dependent systemic circulation
  • Nodular calcific aortic valve stenosis
  • Solitary pulmonary trunk with aortic atresia

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to Q23.0: its own notes plus those printed at Chapter 17. A note printed at a category, block or chapter applies to every code under it.

Applicable To

Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.

  • Congenital aortic atresia
  • Congenital aortic stenosis NOS

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

  • congenital stenosis of aortic valve in hypoplastic left heart syndrome (Q23.4)
  • congenital subaortic stenosis (Q24.4)
  • supravalvular aortic stenosis (congenital) (Q25.3)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 17 (Q00-QA1) Congenital malformations, deformations and chromosomal abnormalities applies to 900 codes
  • inborn errors of metabolism (E70-E88)

Notes

General instructions on how these codes are used.

From Chapter 17 (Q00-QA1) Congenital malformations, deformations and chromosomal abnormalities applies to 900 codes
  • Codes from this chapter are not for use on maternal records

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name Q23.0, its category, or a range that includes it.

Excludes1 2

These codes carry an Excludes1 note naming Q23.0: they are not reported together with it, unless the two conditions are unrelated.

  • Q25.3 Supravalvular aortic stenosis
    congenital aortic stenosis NOS (Q23.0)
  • Q25.3 Supravalvular aortic stenosis
    congenital stenosis of aortic valve (Q23.0)

Excludes2 2

These codes carry an Excludes2 note naming Q23.0: its condition is not part of those codes, and both may be reported when the patient has both.

  • I35 Nonrheumatic aortic valve disorders
    aortic valve disorder specified as congenital (Q23.0, Q23.1)
  • I08 Multiple valve diseases
    multiple valve disease specified as nonrheumatic (I34.-, I35.-, I36.-, I37.-, I38.-, Q22.-, Q23.-, Q24.8-) names Q23.-, which includes this code

Use Additional Code 1

These codes say to use an additional code from the note, and Q23.0 is one of the codes named.

  • Q87.88 CTNNB1 syndrome
    congenital heart malformations (Q20.0-Q24.9) names Q20.0-Q24.9, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR MAL001
Cardiac and circulatory congenital anomalies
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Congenital Aortic Valve Stenosis

    aortic valve stenosis that is present at birth.

Patient EducationClinical

Congenital Heart Defects

Congenital heart defects (CHDs) are problems with the structure of the heart. "Congenital" means that that the problems are present at birth. These defects happen when a fetus's heart doesn't develop normally during pregnancy. Congenital heart defects are the most common type of birth defect.

The full article covers:

  • What are congenital heart defects?
  • What causes congenital heart defects?
  • Who is more likely to have a baby with a congenital heart defect?
  • What are the symptoms of congenital heart defects?
  • What other problems do congenital heart defects cause?
  • How are congenital heart defects diagnosed?
  • What are the treatments for congenital heart defects?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert Q23.0 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
746.3 Cong aorta valv stenosis
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About Q23.0Overview

What is the ICD-10 code for congenital stenosis of aortic valve?

The ICD-10-CM code for congenital stenosis of aortic valve is Q23.0 (sometimes written as Q230). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is Q23.0 (Congenital malformations of aortic and mitral valves) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report congenital stenosis of aortic valve on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does Q23.0 group to?

When congenital stenosis of aortic valve is the principal diagnosis on an inpatient stay, it groups to MS-DRG 306, 307, with relative weights from 0.9146 to 1.5457 depending on complications. Higher weights mean higher Medicare reimbursement.

Is Q23.0 a CC or MCC?

CMS lists Q23.0 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 66 closely related codes in its exclusion list.

Is Q23.0 exempt from POA reporting?

Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for congenital stenosis of aortic valve on inpatient claims. The code appears in the Congenital malformations of the circulatory system (Q20-Q28) range of the CMS exempt list.