2026 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 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

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 2026 (October 1, 2025 through September 30, 2026) 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 other POA exempt codes.

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
  • Ebstein-like malformation 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
  • 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

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Anomaly, anomalous(congenital) (unspecified type)
      • mitral (leaflets) (valve)
        • specified NEC
    • Deformity
      • aortic
        • cusp or valve (congenital)
    • Malformation(congenital)
      • aortic valve
        • specified NEC
    • Malformation(congenital)
      • mitral valve
        • specified NEC
    • Quadricuspid aortic valve
    • Supernumerary(congenital)
      • aortic cusps
    • Supernumerary(congenital)
      • cusps, heart valve NEC
        • aortic

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.

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 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About Q23.88Overview

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, 2025 through September 30, 2026.

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 0.9132 to 1.5758 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.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.