2027 ICD-10-CM Diagnosis Code Q23.88Other congenital malformations of aortic and mitral valves

ICD-10-CM Codes›Q00-Q99›Q20-Q28›Q23

ICD-10-CM Q23.88
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

Q23.88 is a billable ICD-10-CM diagnosis code for other congenital malformations of aortic and mitral valves. 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. The code is exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Cardiac and circulatory congenital anomalies.

Code Identity

ICD-10-CM Code
Q23.88
Billable Status
Yes — Valid for Submission
Code Describes
Other congenital malformations of aortic and mitral valves
Short Description
Other congenital malformations of aortic and mitral valves
Same as the full description in the CMS dataset.
Parent Code
Q23.8
Other 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 CodeQ23.88Other congenital malformations of aortic and mitral valves

Present on Admission (POA)Billing

Q23.88 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.

  • Abnormal number of aortic valve cusps
  • Abnormal relationship of aortic orifice to pulmonary orifice
  • Abnormality of mitral valve annulus
  • Absent aortic valve cusp
  • Absent mitral leaflets
  • Accessory tissue on aortic valve cusp
  • Accessory tissue on mitral leaflet
  • Acommissural unicuspid aortic valve
  • Anterior leaflet of mitral valve attached to septum
  • Aortic orifice anterior left with respect to pulmonary orifice
  • Aortic orifice anterior right with respect to pulmonary orifice
  • Aortic orifice anterior with respect to pulmonary orifice
  • Aortic orifice left side by side with respect to pulmonary orifice
  • Aortic orifice posterior left with respect to pulmonary orifice
  • Aortic orifice posterior with respect to pulmonary orifice
  • Aortic orifice right side by side with respect to pulmonary orifice
  • Aortic valve dysplasia
  • Aortic valve overriding ventricular septum
  • Cleft leaflet of mitral valve
  • Congenital abnormal shape of aortic valve
  • Congenital abnormal shape of mitral valve
  • Congenital abnormality of arterial valves
  • Congenital abnormality of mitral subvalvular apparatus
  • Congenital absence of aortic valve
  • Congenital absence of mitral valve
  • Congenital billowing of mitral valve leaflet
  • Congenital cleft of cardiac valve
  • Congenital deformity of mitral valve annulus
  • Congenital dysplasia of aortic valve
  • Congenital dysplasia of cardiac valve
  • Congenital hypertrophy of aortic valve
  • Congenital hypertrophy of mitral valve
  • Congenital hypoplasia of annulus fibrosus of aorta
  • Congenital hypoplasia of aortic valve
  • Congenital hypoplasia of mitral valve
  • Congenital mass of mitral leaflet
  • Congenital midvalvar ring of mitral leaflet
  • Congenital prolapse of mitral valve
  • Continuity between aortic valve and mitral valve
  • Continuity between mitral valve and pulmonary valve
  • Discontinuity between mitral valve and pulmonary valve
  • Double aortic valve
  • Double mitral valve
  • Double orifice of mitral valve
  • Ebstein-like downward displacement of mitral valve
  • Eccentric opening of aortic valve
  • Eccentric opening of tricuspid aortic valve
  • Fused commissures of mitral valve
  • Hypoplasia of mitral valve annulus
  • Hypoplasia of trabecular portion of left ventricle
  • Hypoplastic mitral papillary muscle
  • Left ventricular hypoplasia
  • Mitral papillary muscle abnormality
  • Overriding mitral valve
  • Parachute malformation of mitral valve
  • Quadricuspid aortic valve
  • Shone complex
  • Straddling mitral valve
  • Structural abnormality of trabeculae carnea of left ventricle
  • Supramitral left atrial ring
  • Tricuspid but functionally bicuspid aortic valve
  • Unicommissural unicuspid aortic valve
  • Unicuspid aortic valve
  • Ventricular septal defect with anterior malaligned outlet septum with overriding aortic valve
  • Ventricular septal defect with posterior malaligned outlet septum with overriding aortic valve

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to Q23.88: its own notes plus those printed at Chapter 17. A note printed at a category, block or chapter applies to every code under it.

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 Q23.88, its category, or a range that includes it.

Excludes2 1

These codes carry an Excludes2 note naming Q23.88: its condition is not part of those codes, and both may be reported when the patient has both.

  • 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 Q23.88 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

  • Quadricuspid Aortic Valve

    congenital malformation where the aortic valve has four instead of three cusps. it is often associated with aortic regurgitation and aortic valve stenosis.

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.

Code History & ChangesHistory

Replacement Q23.88 replaces the following previously assigned code(s):

  • Q23.8 - Other congenital malformations of aortic and mitral valves
FY 2025AddedAdded to the ICD-10-CM code setEffective October 1, 2024.
FY 2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About Q23.88Overview

What is the ICD-10 code for other congenital malformations of aortic and mitral valves?

The ICD-10-CM code for other congenital malformations of aortic and mitral valves is Q23.88 (sometimes written as Q2388). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is Q23.88 (Other congenital malformations of aortic and mitral valves) a billable code?

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

What MS-DRG does Q23.88 group to?

When other congenital malformations of aortic and mitral valves 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 Q23.88 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 other congenital malformations of aortic and mitral valves on inpatient claims. The code appears in the Congenital malformations of the circulatory system (Q20-Q28) range of the CMS exempt list.