Q28.9 Congenital malformation of circulatory system, unspecified

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis. Exempt from present-on-admission (POA) reporting.

Applies from Q28 Other congenital malformations of circulatory system

Excludes1 (never code together)

• congenital aneurysm NOS (Q27.8)
• congenital coronary aneurysm (Q24.5)
• ruptured cerebral arteriovenous malformation (I60.8)
• ruptured malformation of precerebral vessels (I72.0)

Excludes2 (not included here)

• congenital peripheral aneurysm (Q27.8)
• congenital pulmonary aneurysm (Q25.79)
• congenital retinal aneurysm (Q14.1)

MS-DRG index

Defines the logic of DRG(s) 299-301 in MDC 05.

Approximate ICD-9-CM (GEMs)

• 747.9 Unspecified anomaly of circulatory system

Code annotations containing back-references to Q28.9

Back-references to Q28

• Code Also: I27.21 Secondary pulmonary arterial hypertension ("congenital heart disease (Q20-Q28)")
• Type 1 Excludes: I67.1 Cerebral aneurysm, nonruptured ("congenital cerebral aneurysm, nonruptured (Q28.-)")
• Type 2 Excludes: P29 Cardiovascular disorders originating in the perinatal period ("congenital malformations of the circulatory system (Q20-Q28)")
• Code Also: Z71.87 Encounter for pediatric-to-adult transition counseling ("congenital malformations of the circulatory system (Q20-Q28)")

Diagnosis Index entries for Q28.9

• Agenesis › circulatory system, part NOS
• Anomaly, anomalous (congenital) (unspecified type) › circulatory system
• Circulation › defective (lower extremity) › congenital
• Circulation › embryonic
• Circulation › heart, incomplete
• Defect, defective › circulation › congenital
• Defect, defective › circulation › newborn
• Deformity › cardiovascular system, congenital
• Disease, diseased › cardiovascular (atherosclerotic) › congenital
• Embryonic › circulation
• Embryonic › heart
• Malformation (congenital) › circulatory system

Nearby codes

• Q28.0 Arteriovenous malformation of precerebral vessels
• Q28.1 Other malformations of precerebral vessels
• Q28.2 Arteriovenous malformation of cerebral vessels
• Q28.3 Other malformations of cerebral vessels
• Q28.8 Other specified congenital malformations of circulatory system
• Q28.9 Congenital malformation of circulatory system, unspecified (this code)