Q28.1Other malformations of precerebral vessels

Q28.1 is the ICD-10-CM diagnosis code for other malformations of precerebral vessels. It belongs to category Q28 (other congenital malformations of circulatory system), block Q20-Q28 (congenital malformations of the circulatory system) and chapter 17 (congenital malformations, deformations, chromosomal abnormalities, and genetic disorders). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within Q28, choose Q28.1 (Other malformations of precerebral vessels) only when documentation doesn't support a more specific option: arteriovenous malformation of precerebral vessels (Q28.0), arteriovenous malformation of cerebral vessels (Q28.2), other malformations of cerebral vessels (Q28.3), other specified congenital malformations of circulatory system (Q28.8) and congenital malformation of circulatory system, unspecified (Q28.9).

As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 299 (Peripheral Vascular Disorders with MCC, relative weight 1.5842), DRG 300 (Peripheral Vascular Disorders with CC, relative weight 1.0464) and DRG 301 (Peripheral Vascular Disorders without CC/MCC, relative weight 0.7133), in MDC 05 (Diseases and Disorders of the Circulatory System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It is exempt from present-on-admission (POA) reporting, so no POA indicator is required.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 747.89 (other specified anomalies of circulatory system).