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ICD-10-CM I63.9: Cerebral infarction, unspecified

I63.9 is the billable ICD-10-CM code for cerebral infarction, unspecified, in category I63 (Cerebral infarction) of the Cerebrovascular diseases section. As a principal diagnosis it groups to MS-DRG 023 Craniotomy with Major Device Implant or Acute Complex CNS Principal Diagnosis with MCC or Antineoplastic Implant or Epilepsy with Neurostimulator, MS-DRG 024 Craniotomy with Major Device Implant or Acute Complex CNS Principal Diagnosis without MCC, MS-DRG 061 Ischemic Stroke, Precerebral Occlusion or Transient Ischemia with Thrombolytic Agent with MCC (MDC 01 MDC 01: Diseases and Disorders of the Nervous System); or MS-DRG 791 Prematurity with Major Problems, MS-DRG 793 Full Term Neonate with Major Problems (MDC 15 MDC 15: Newborns and Other Neonates with Conditions Originating in Perinatal Period). It maps to HCC 249 (Ischemic or Unspecified Stroke) in CMS-HCC V28. As a secondary diagnosis it is an MCC, excluded with 84 principal diagnoses. 29 LCD billing and coding articles list it as covered.

Compiled from CMS files by the QuickIntell RCM Editorial Team · Data effective · Method: reference methodology · Report a data correction

Data currency: ICD-10-CM code descriptions: FY2027 (effective October 1, 2026); IPPS Table 5 (MS-DRG weights): v44 FY2027 (final rule + CN3) (effective October 1, 2026); ICD-10-CM to HCC mapping: PY2027 initial ICD-10-CM mappings (dates of service 2026) (payment year 2027); Medicare Coverage Database billing and coding articles: MCD release October 8, 2026 (effective October 4, 2026). Next CMS release: FY2028 code files, effective October 1, 2027 for the ICD-10-CM code descriptions; FY2028 final rule (August 2027), effective October 1, 2027; an April 1 interim grouper update when CMS issues one for the IPPS Table 5 (MS-DRG weights); PY2028 advance notice (February 2027) and the PY2027 midyear final mapping (spring 2027) for the ICD-10-CM to HCC mapping; weekly, every Thursday for the Medicare Coverage Database billing and coding articles.

Code
I63.9
billable FY2027 ICD-10-CM code
Category
I63 Cerebral infarction
Chapter
9: Diseases of the circulatory system (I00-I99)
CC/MCC (MS-DRG v44)
MCC
CMS-HCC V28
HCC 249
POA reporting
Required

Tabular list notes for I63.9

Inclusion terms
  • Stroke NOS
Excludes2 (not part of this condition, may be coded together)
  • transient cerebral ischemic attacks and related syndromes (G45.-)

Inherited from I63 (Cerebral infarction)

Includes
  • occlusion and stenosis of cerebral and precerebral arteries, resulting in cerebral infarction
Excludes1 (never coded together)
  • neonatal cerebral infarction (P91.82-)
Excludes2 (not part of this condition, may be coded together)
  • chronic, without residual deficits (sequelae) (Z86.73)
  • sequelae of cerebral infarction (I69.3-)
Use additional code
  • code, if applicable, to identify status post administration of tPA (rtPA) in a different facility within the last 24 hours prior to admission to current facility (Z92.82)
  • code, if known, to indicate National Institutes of Health Stroke Scale (NIHSS) score (R29.7-)

MS-DRG grouping when I63.9 is the principal diagnosis

MS-DRG v44 groups for I63.9 as principal diagnosis
MDCMS-DRGs
01 MDC 01: Diseases and Disorders of the Nervous System023024061062063064065066
15 MDC 15: Newborns and Other Neonates with Conditions Originating in Perinatal Period791793

The final group also depends on procedures, secondary diagnoses and discharge status; the MS-DRG lookup for I63.9 shows the full grouping logic.

CC/MCC status and inpatient edits

As a secondary diagnosis, I63.9 is an MCC under MS-DRG v44, unless the principal diagnosis is one of the 84 codes in its exclusion list. Check I63.9 against a principal diagnosis.

  • Present on admission: a POA indicator is required on inpatient claims.

CMS-HCC V28 risk adjustment

In the PY2027 mapping, I63.9 maps to HCC 249 (Ischemic or Unspecified Stroke). The HCC lookup shows the RAF weight and the hierarchy.

LCD billing and coding articles that list I63.9

29 current Medicare billing and coding articles list I63.9 among the diagnoses that support medical necessity for the services they cover.

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Frequently asked questions

What does ICD-10-CM I63.9 mean?

I63.9 means cerebral infarction, unspecified. The tabular list also files these terms under it: Stroke NOS. It is one of 25 billable codes under I63, cerebral infarction.

What can't be coded with I63.9?

Excludes1 at I63: neonatal cerebral infarction (P91.82-). These are never reported together with I63.9.

Which MS-DRG does I63.9 group to?

As the principal diagnosis, I63.9 groups to MS-DRG 023 Craniotomy with Major Device Implant or Acute Complex CNS Principal Diagnosis with MCC or Antineoplastic Implant or Epilepsy with Neurostimulator, MS-DRG 024 Craniotomy with Major Device Implant or Acute Complex CNS Principal Diagnosis without MCC, MS-DRG 061 Ischemic Stroke, Precerebral Occlusion or Transient Ischemia with Thrombolytic Agent with MCC (MDC 01 MDC 01: Diseases and Disorders of the Nervous System); or MS-DRG 791 Prematurity with Major Problems, MS-DRG 793 Full Term Neonate with Major Problems (MDC 15 MDC 15: Newborns and Other Neonates with Conditions Originating in Perinatal Period) under MS-DRG v44, before procedures and secondary diagnoses are applied.

Does I63.9 map to an HCC?

Yes: HCC 249, Ischemic or Unspecified Stroke, in the PY2027 CMS-HCC V28 mapping.

Is I63.9 a CC or MCC?

I63.9 is an MCC under MS-DRG v44; 84 principal diagnoses exclude it.

Sources

Every figure on this page is taken from the CMS publications below, as released by the Centers for Medicare & Medicaid Services. Projection built 2026-10-10. Verify against the primary file before billing or contracting decisions. The reference methodology explains how each figure is computed from these files.

Disclaimer

The descriptor and notes are reproduced from the FY2027 ICD-10-CM files; MS-DRG, CC/MCC and HCC facts come from the CMS FY2027 and PY2027 tables. Code from the medical record and the ICD-10-CM Official Guidelines. Not legal, clinical or billing advice.

Found a figure that does not match the CMS file? Report a data correction with the CMS file and the value you expected; the request reaches the editorial team through the contact form.