Version 2024

2024 ICD-10-CM Diagnosis Code Q21.20

Atrioventricular septal defect, unspecified as to partial or complete

ICD-10-CM Code:: Q21.20
ICD-10 Code for:: Atrioventricular septal defect, unsp as to part or complete
Is Billable?: Yes - Valid for Submission
Chronic Condition Indicator: ^[1]: Chronic
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Code Information
Approximate Synonyms
Clinical Classification
Clinical Information
Tabular List of Diseases and Injuries
Index to Diseases and Injuries References
Diagnostic Related Groups Mapping
Present on Admission (POA)
Replacement Code
Patient Education
Other Codes Used Similar Conditions
Code History

Code Classification

Congenital malformations, deformations and chromosomal abnormalities
(Q00-Q99)
- Congenital malformations of the circulatory system
  (Q20-Q28)
  - Congenital malformations of cardiac septa
    (Q21)

Q21.20 is a billable diagnosis code used to specify a medical diagnosis of atrioventricular septal defect, unspecified as to partial or complete. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2023 through September 30, 2024. The code is exempt from present on admission (POA) reporting for inpatient admissions to general acute care hospitals.

Unspecified diagnosis codes like Q21.20 are acceptable when clinical information is unknown or not available about a particular condition. Although a more specific code is preferable, unspecified codes should be used when such codes most accurately reflect what is known about a patient's condition. Specific diagnosis codes should not be used if not supported by the patient's medical record.

Approximate Synonyms

The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

Abnormality of atrioventricular valve leaflet in atrioventricular septal defect
Atrioventricular septal defect - isolated atrial component
Atrioventricular septal defect - isolated ventricular component
Atrioventricular septal defect - ventricular component
Atrioventricular septal defect - ventricular component under inferior bridging leaflet
Atrioventricular septal defect - ventricular component under inferior bridging leaflet
Atrioventricular septal defect - ventricular component under superior bridging leaflet
Atrioventricular septal defect - ventricular component under superior bridging leaflet
Atrioventricular septal defect - ventricular component under superior bridging leaflet
Atrioventricular septal defect - ventricular component under superior bridging leaflet
Atrioventricular septal defect - ventricular component under superior bridging leaflet
Atrioventricular septal defect associated with tetralogy of Fallot
Atrioventricular septal defect with additional muscular ventricular septal defect
Atrioventricular septal defect with atrial and ventricular components and separate atrioventricular valves
Atrioventricular septal defect with atrioventricular valve regurgitation
Atrioventricular septal defect with atrioventricular valve regurgitation
Atrioventricular septal defect with atrioventricular valve regurgitation
Atrioventricular septal defect with atrioventricular valve regurgitation
Atrioventricular septal defect with atrioventricular valve regurgitation
Atrioventricular septal defect with atrioventricular valve regurgitation
Atrioventricular septal defect with atrioventricular valve regurgitation
Atrioventricular septal defect with atrioventricular valve regurgitation
Atrioventricular septal defect with atrioventricular valve regurgitation through left inferior bridging leaflet lateral mural commissure
Atrioventricular septal defect with atrioventricular valve regurgitation through left septal commissure
Atrioventricular septal defect with atrioventricular valve regurgitation through left superior bridging leaflet lateral mural commissure
Atrioventricular septal defect with atrioventricular valve regurgitation through right anterosuperior inferior mural commissure
Atrioventricular septal defect with atrioventricular valve regurgitation through right anterosuperior superior bridging leaflet commissure
Atrioventricular septal defect with atrioventricular valve regurgitation through right inferior bridging leaflet inferior mural commissure
Atrioventricular septal defect with atrioventricular valve regurgitation through right septal commissure
Atrioventricular septal defect with balanced ventricles
Atrioventricular septal defect with restrictive ventricular component
Atrioventricular septal defect with separate atrioventricular orifices
Atrioventricular septal defect with ventricular component and interchordal shunting under inferior bridging leaflet
Atrioventricular septal defect with ventricular component and interchordal shunting under superior bridging leaflet
Atrioventricular septal defect with ventricular component and shunting under connecting tongue with separate orifices
Atrioventricular septal defect with ventricular component under free floating superior bridging leaflet and chords to papillary muscle at right ventricular free wall
Atrioventricular septal defect with ventricular component under inferior bridging leaflet with chords to crest ventricular septum
Atrioventricular septal defect with ventricular component under superior bridging leaflet with chords at crest ventricular septum
Atrioventricular septal defect with ventricular component under superior bridging leaflet with chords to papillary muscle on right ventricular side septum
Atrioventricular septal defect with ventricular component under superior bridging leaflet without chordal attachment to ventricular septal crest
Atrioventricular septal defect with ventricular imbalance
Atrioventricular septal defect with ventricular imbalance consisting of dominant left ventricle and hypoplastic right ventricle
Atrioventricular septal defect with ventricular imbalance consisting of dominant right ventricle and hypoplastic left ventricle
Atrioventricular septal defect, blepharophimosis, radial and anal defect syndrome
Atrioventricular septal defect: atrial and ventricular components
Common atrioventricular canal
Common atrioventricular-type ventricular septal defect
Common atrium
Congenital abnormality of atrioventricular valve leaflet in atrioventricular septal defect
Congenital abnormality of atrioventricular valve papillary muscle in atrioventricular septal defect
Congenital abnormality of atrioventricular valves in atrioventricular septal defect
Congenital atrioventricular septal defect
Congenital blepharophimosis
Deficiency of atrioventricular valve leaflet in atrioventricular septal defect
Endocardial cushion defect
Endocardial cushion defect
Fenestration of atrioventricular valve leaflet in atrioventricular septal defect
Flail atrioventricular valve leaflet in atrioventricular septal defect
Gelatinous atrioventricular valve leaflet in atrioventricular septal defect
Mass associated with atrioventricular valve leaflet in atrioventricular septal defect
Noncoapting atrioventricular valve leaflet in atrioventricular septal defect
Ostium primum defect
Residual interatrial communication
Spontaneous closure of atrial component of atrioventricular septal defect
Spontaneous closure of ventricular component of atrioventricular septal defect
Spontaneous closure of ventricular septal defect
Spontaneous closure of ventricular septal defect due to accessory tissue of atrioventricular valve
Thickened atrioventricular valve leaflet in atrioventricular septal defect
Ventricular imbalance

Clinical Classification

Clinical Category is Cardiac and circulatory congenital anomalies
CCSR Category Code: MAL001
Inpatient Default CCSR: Y - Yes, default inpatient assignment for principal diagnosis or first-listed diagnosis.
Outpatient Default CCSR: Y - Yes, default outpatient assignment for principal diagnosis or first-listed diagnosis.

Clinical Information

Ostium Primum Defect
a congenital defect in the atrial septum at the level of the atrioventricular valves, resulting in abnormalities in the mitral and/or tricuspid valve; this defect is most commonly seen in those with trisomy 21.

Tabular List of Diseases and Injuries

The following annotation back-references are applicable to this diagnosis code. The Tabular List of Diseases and Injuries is a list of ICD-10-CM codes, organized "head to toe" into chapters and sections with coding notes and guidance for inclusions, exclusions, descriptions and more.

Inclusion Terms

Atrioventricular canal, NOS
Endocardial cushion defect NOS
Ostium primum atrial septal defect (type I) NOS

Index to Diseases and Injuries References

The following annotation back-references for this diagnosis code are found in the injuries and diseases index. The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10-CM code(s).

- Canal - See Also: condition;
- - atrioventricular - Q21.20

- Defect, defective - Q89.9
- - atrial septal - Q21.10
  - - ostium primum type (type I) - Q21.20
- - atrioventricular
  - - canal - Q21.20
  - - septal
    - - unspecified as to partial or complete - Q21.20
  - - septum - Q21.20
- - cushion, endocardial - Q21.20
- - ostium
  - - primum - Q21.20

- Endocardium, endocardial - See Also: condition;
- - cushion defect - Q21.20

- Imperfect
- - closure (congenital)
  - - atrioventricular ostium - Q21.20

- Ostium
- - primum (arteriosum) (defect) (persistent) - Q21.20

- Persistence, persistent (congenital)
- - atrioventricular canal - Q21.20
- - ostium
  - - primum - Q21.20

- Single
- - atrium - Q21.20

Q21.20 is grouped with Diagnostic Related Groups - MS-DRG Mapping

Diagnostic Related Groups (DRGs) are a classification system used to group together diagnosis codes for the purpose of reimbursement and healthcare management. DRGs are used to standardize the way hospitals and other providers are paid for inpatient services. In this system patients are grouped together based on their principal diagnosis in areas referred to as Major Diagnostic Categories (MDC). Once a patient is assigned a particular diagnostic category, providers receive a predetermined payment rate for the services rendered. This reimbursement rate is often fixed and is meant to cover the cost of care for that patient. Reimbursement is also affected by the relative weight of a diagnostic related group based on the severity of a patient's illness and the associated cost of care during hospitalization.

Diagnostic related groups encourage healthcare providers to focus on quality and efficiency in patient care while managing costs effectively. The diagnosis code is present in the following groups for version MS-DRG V41.0 applicable from 10/01/2023 through 09/30/2024.

MS-DRG	MS-DRG Title	MCD	Relative Weight
306	CARDIAC CONGENITAL AND VALVULAR DISORDERS WITH MCC	05	1.5368
307	CARDIAC CONGENITAL AND VALVULAR DISORDERS WITHOUT MCC	05	0.9426

The relative weight of a diagnostic related group determines the reimbursement rate based on the severity of a patient's illness and the associated cost of care during hospitalization.

Present on Admission (POA)

Q21.20 is exempt from POA reporting - The Present on Admission (POA) indicator is used for diagnosis codes included in claims involving inpatient admissions to general acute care hospitals. POA indicators must be reported to CMS on each claim to facilitate the grouping of diagnoses codes into the proper Diagnostic Related Groups (DRG). CMS publishes a listing of specific diagnosis codes that are exempt from the POA reporting requirement. Review other POA exempt codes here.

CMS POA Indicator Options and Definitions

POA Indicator	Reason for Code	CMS will pay the CC/MCC DRG?
Y	Diagnosis was present at time of inpatient admission.	YES
N	Diagnosis was not present at time of inpatient admission.	NO
U	Documentation insufficient to determine if the condition was present at the time of inpatient admission.	NO
W	Clinically undetermined - unable to clinically determine whether the condition was present at the time of inpatient admission.	YES
1	Unreported/Not used - Exempt from POA reporting.	NO

Replacement Code

Q2120 replaces the following previously assigned ICD-10-CM code(s):

Q21.2 - Atrioventricular septal defect

Code History

FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
FY 2023 - Code Added, effective from 10/1/2022 through 9/30/2023

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.