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

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

Tabular directives
2 inclusion terms · 2 Excludes1 · 3 Excludes2 · 10 use-additional codes
Risk adjustment
CMS-HCC V28: 1 category · CMS-HCC V22 category 100

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v44, Appendix B.

  • MS-DRG 023 — CRANIOTOMY WITH MAJOR DEVICE IMPLANT OR ACUTE COMPLEX CNS PRINCIPAL DIAGNOSIS WITH MCC OR ANTINEOPLASTIC IMPLANT OR EPILEPSY WITH NEUROSTIMULATOR (MDC 01)
  • MS-DRG 024 — CRANIOTOMY WITH MAJOR DEVICE IMPLANT OR ACUTE COMPLEX CNS PRINCIPAL DIAGNOSIS WITHOUT MCC (MDC 01)
  • MS-DRG 061 — ISCHEMIC STROKE, PRECEREBRAL OCCLUSION OR TRANSIENT ISCHEMIA WITH THROMBOLYTIC AGENT WITH MCC (MDC 01)
  • MS-DRG 062 — ISCHEMIC STROKE, PRECEREBRAL OCCLUSION OR TRANSIENT ISCHEMIA WITH THROMBOLYTIC AGENT WITH CC (MDC 01)
  • MS-DRG 063 — ISCHEMIC STROKE, PRECEREBRAL OCCLUSION OR TRANSIENT ISCHEMIA WITH THROMBOLYTIC AGENT WITHOUT CC/MCC (MDC 01)
  • MS-DRG 064 — INTRACRANIAL HEMORRHAGE OR CEREBRAL INFARCTION WITH MCC (MDC 01)
  • MS-DRG 065 — INTRACRANIAL HEMORRHAGE OR CEREBRAL INFARCTION WITH CC OR TPA IN 24 HOURS (MDC 01)
  • MS-DRG 066 — INTRACRANIAL HEMORRHAGE OR CEREBRAL INFARCTION WITHOUT CC/MCC (MDC 01)
  • MS-DRG 791 — PREMATURITY WITH MAJOR PROBLEMS (MDC 15)
  • MS-DRG 793 — FULL TERM NEONATE WITH MAJOR PROBLEMS (MDC 15)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Risk Adjustment (CMS-HCC)

Payment categories this diagnosis maps to under CMS-HCC V28, payment year 2026.

  • HCC 249 — Ischemic or Unspecified Stroke

Other models: CMS-HCC V22 HCC 100

Risk scores depend on the enrollee's full accepted diagnosis set and segment; a category mapping alone does not determine payment.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for I63.9 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2027Effective: October 1, 2026

Trace:FY2027 changesChange historyRelease, file and checksum

Notes without a marker are published on I63.9 itself; “inherited from” names the category or block whose note applies here.

Includes

Conditions the official ICD-10-CM tabular list includes under this code.

  • occlusion and stenosis of cerebral and precerebral arteries, resulting in cerebral infarction

Source: inherited from I63

Inclusion Terms

Alternative terms the tabular list files under this code.

  • Stroke NOS

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

Use Additional Code

Supplementary codes the tabular list directs you to add.

  • Use additional 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) inherited from I63
  • Use additional code, if known, to indicate National Institutes of Health Stroke Scale (NIHSS) score (R29.7-) inherited from I63
  • Use additional code to identify presence of:
  • alcohol abuse and dependence (F10.-) inherited from I60-I69
  • exposure to environmental tobacco smoke (Z77.22) inherited from I60-I69
  • history of tobacco dependence (Z87.891) inherited from I60-I69
  • hypertension (I10-I1A) inherited from I60-I69
  • occupational exposure to environmental tobacco smoke (Z57.31) inherited from I60-I69
  • tobacco dependence (F17.-) inherited from I60-I69
  • tobacco use (Z72.0) inherited from I60-I69

Coder workflow for I63.9

MedCoder structured workflow — derived from this code’s own official record

Before you code I63.9

  1. Unspecified does not mean incorrect. When the record gives no greater specificity, I63.9 may be the appropriate code. Check the record for detail that supports a more specific sibling. An unspecified code is for records that do not provide the detail a more specific code needs; a query, not an assumption, is the route to specificity (Guidelines I.A.9.b, I.B.18).

    ReviewI63.6, I63.8

    See the relationships section · Guide: Other vs unspecified (NEC vs NOS) →

  2. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with I63.9. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).

    See the official tabular notes

Choose the right path

  1. Does the record document the detail a more specific sibling code needs?
    Yes → Review the specific siblings in this subcategory.
    No → Continue — I63.9 is appropriate when the documentation goes no further.

    ReviewI63.6, I63.8

  2. Does the documentation support a condition named in I63.9’s Excludes1 note?
    Yes → Do not simply proceed: review the excluded code. Both are reported only when the record shows the two conditions are unrelated.
    No → Continue.

    ReviewP91.82, S06

Consider I63.9. Then work the Use Additional Code note, and confirm the code is valid for the date of service in the Verify section.

Documentation check

The provider’s diagnostic statement
Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).
The conditions the Use Additional Code note names
Reported with this code when documented; a conditional instruction (“if applicable”, “if known”) applies only when the record supports it.
Any detail beyond this code’s title
What the record states that a more specific sibling code would capture — or its absence, which itself supports the unspecified code.

Official instructions as workflow

  • Excludes1 — check before selecting I63.9(2 notes)

    Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with I63.9: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

    CompareP91.82, S06

    See the official tabular notes · Guidelines I.A.12.a

  • Excludes2 — not part of I63.9(3 notes)

    Coding workflow: The conditions named in this note are not included in I63.9. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareG45, Z86.73, I69.3

    See the official tabular notes · Guidelines I.A.12.b

  • Use Additional Code — after identifying I63.9(10 notes)

    Coding workflow: Check whether the documentation supports the additional code(s) the note names, and report them with I63.9 when it does. Where the instruction is conditional (“if applicable”, “if known”), it applies only when the record documents the condition.

    ReviewZ92.82, R29.7, F10, Z77.22, Z87.891, Z57.31

    See the official tabular notes · Guidelines I.A.13

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Before you code I63.9

MedCoder editorial — not official ICD-10-CM text; reviewed against the cited source

This checklist routes you to the categories to review — it does not determine the final code.

I63.9 is an acute-event code — a cerebral infarction happening now, with no documented mechanism or vessel. The commonest wrong turns are temporal: coding an old stroke as if acute, or an acute stroke as history. Check for these before settling on I63.9.

  • Mechanism or vessel documented — thrombosis, embolism, stenosis, a named artery → the specific I63.- rows

    I63.9 is "Stroke NOS"; a documented mechanism and vessel select a specific I63 row.

  • Past infarction with documented residual deficits → I69.3- Sequelae of cerebral infarction

    I63’s Excludes2 splits the aftermath: documented residuals belong to the I69.3- sequela rows, coded with the specific deficit.

  • Past infarction with no residual deficits documented → Z86.73 Personal history of TIA/cerebral infarction

    The other half of the split — "chronic, without residual deficits" is I63’s own Excludes2 pointer to the history code, and Z86.73’s Excludes1 bars it when sequelae exist.

  • Deficits resolved within the episode — TIA documented → G45.- Transient cerebral ischemic attacks

    A TIA is not an infarction — I63.9 carries an Excludes2 routing it to G45.-.

  • tPA given at another facility within the last 24 hours → Z92.82 as an additional code

    Category I63’s Use Additional Code note asks for it — an inpatient-coding companion that is easy to drop at transfer.

  • NIHSS score documented → R29.7- as an additional code

    The category’s second Use Additional Code note — report the score code when known.

The acute-vs-sequela-vs-history split that decides the first three rows is worked through in the sequela guide. Sequela (Late Effects) Coding →

Provider documentation and the ICD-10-CM Official Guidelines control; verify against the official tabular notes on this page.

Don’t confuse I63.9 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of I63.9 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

  • P91.82— Excludes1 conflict (Excludes1 — generally not reported together)

    Not coded here — the tabular list excludes this pair for the same encounter.

    Not reported together with this code, except where the two conditions are documented as unrelated.

    What moves you there: Documentation of neonatal cerebral infarction moves the case to P91.82; the two are not reported together unless documented as unrelated.

    Full comparison: I63.9 vs P91.82 →

  • S06— Excludes1 conflict (Excludes1 — generally not reported together)

    Not coded here — the tabular list excludes this pair for the same encounter.

    Not reported together with this code, except where the two conditions are documented as unrelated.

    What moves you there: Documentation of traumatic intracranial hemorrhage moves the case to S06; the two are not reported together unless documented as unrelated.

    Full comparison: I63.9 vs S06 →

  • G45— Excludes2 relationship (Informational)

    Distinct conditions — both may be reported.

    A distinct condition — both may be reported when both are documented.

    What moves you there: Documentation of transient cerebral ischemic attacks and related syndromes adds G45; it is not part of this code and both may be reported when both are documented.

    Full comparison: I63.9 vs G45 →

  • Z86.73— Excludes2 relationship (Informational)

    Distinct conditions — both may be reported.

    A distinct condition — both may be reported when both are documented.

    What moves you there: Documentation of chronic, without residual deficits (sequelae) adds Z86.73; it is not part of this code and both may be reported when both are documented.

    Full comparison: I63.9 vs Z86.73 →

  • I69.3— Excludes2 relationship (Informational)

    Distinct conditions — both may be reported.

    A distinct condition — both may be reported when both are documented.

    What moves you there: Documentation of sequelae of cerebral infarction adds I69.3; it is not part of this code and both may be reported when both are documented.

    Full comparison: I63.9 vs I69.3 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Code Overview

Cerebral infarction, unspecified is a billable ICD-10-CM diagnosis code (I63.9).

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Indexed Clinical Terms (16)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

Official Coding Guidelines

Official source data — quoted verbatim from the CMS/NCHS Official Guidelines

Official source data — quoted verbatim from the CMS/NCHS Official Guidelines

Verbatim excerpts from the ICD-10-CM Official Guidelines for Coding and Reporting (CMS/NCHS) that govern this code.

Chapter 18: Symptoms, signs, and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99)

i. NIHSS Stroke Scale The NIH stroke scale (NIHSS) codes (R29.7- -) can be used in conjunction with acute stroke codes (I60-I63) to identify the patient's neurological status and the severity of the stroke. The stroke scale codes should be sequenced after the acute stroke diagnosis code(s).

Coding Notes

MedCoder editorial — not official ICD-10-CM text; reviewed against the cited source

What this code means

I63.9 reports an acute cerebral infarction — “Stroke NOS” is its inclusion term — when neither the mechanism (thrombosis, embolism, stenosis) nor the vessel is documented. It is an acute-event code: a later encounter focused on the history of the infarction or its residual effects, rather than the current acute infarction, moves to Z86.73 (no residual deficits documented) or the I69.3- sequela codes (documented residuals), a split the code’s own Excludes2 notes spell out.

Coding guidance

  • The Use Additional Code note is a checklist worth reading verbatim on the code page: tPA at another facility within 24 hours (Z92.82), the NIHSS score (R29.7-), hypertension (I10–I1A), tobacco and alcohol codes, and the exposure codes.
  • A TIA is not an infarction — transient cerebral ischemic attacks route to G45.- under an Excludes2.
  • Traumatic intracranial hemorrhage is an Excludes1 (S06.-): a documented traumatic mechanism leaves this code.
  • A documented mechanism and vessel select a specific I63 row instead of I63.9 — the category encodes both axes in its own subdivisions.

Decision-rule scenarios

Documentation: A patient is seen in follow-up two months after a stroke; the record documents residual right-sided weakness.

Coding question: Is I63.9 still reported?

Rule: No — the acute-event code belongs to the acute encounter. Documented residuals select the I69.3- sequela codes, and a deficit-free recovery selects Z86.73; the deciding element is whether deficits are documented at this encounter.

Documentation: The chart documents “acute ischemic stroke, left MCA thrombosis.”

Coding question: Does I63.9 apply?

Rule: No — a documented mechanism and vessel select the specific I63 row. I63.9 is for records that state neither; the deciding elements are the mechanism and artery wording.

Scenarios state the decision rule, not a code assignment — code selection always follows the provider's documentation and the ICD-10-CM Official Guidelines.

Documentation checklist

  • The mechanism (thrombosis, embolism, occlusion/stenosis) and the artery, which select a specific I63 row.
  • The NIHSS score and any tPA given at a transferring facility (each has its own additional code).
  • Contributing conditions the Use Additional note names: hypertension, tobacco, alcohol.
  • At later encounters: whether residual deficits remain — the Z86.73 versus I69.3- fork.

Codes are assigned from provider documentation; a coder never infers a diagnosis.

Common mistakes

  • Carrying I63.9 forward onto later encounters for the history or residuals of the infarction — those move to Z86.73 or I69.3-.
  • Coding a documented TIA as an infarction — G45.- claims it.
  • Skipping the NIHSS and Z92.82 additional codes the note asks for when documented.

Clinical context (coding perspective)

“CVA” in older charts covers both infarction and hemorrhage; the I63 family is the ischemic side only. Hemorrhages live in I60–I62, which is why the coder confirms the type before the mechanism.

Written and reviewed by MedCoder against the official ICD-10-CM files; educational, not medical or billing advice. The official tabular notes and guidelines above take precedence in every case.

Decision Points

The directives on this code's own record, as a pre-claim checklist.

  1. 10 Use Additional Code instructions — report the named additional code(s) when the documentation supports them. See the Use Additional Code notes
  2. 2 Excludes1 entries — codes named there are generally not reported together with this code (Guidelines I.A.12.a). See the Excludes1 notes
  3. 3 Excludes2 entries — those conditions are not part of this code and may be reported additionally when documented. See the Excludes2 notes

Checklist rows are derived from this code's own official directives; the wording of each check is MedCoder editorial. The official notes themselves are in the sections each row links to.

Verify Before Coding

  • MCC as a secondary diagnosis (FY2027). Can raise the stay's MS-DRG severity tier.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name I63.9 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 5 Excludes1 notes across 3 chapters: G31.84 — Mild cognitive impairment of uncertain or unknown etiology (via I63.-), I65 — Occlusion and stenosis of precerebral arteries, not resulting in cerebral infarction (via I63.-), I66 — Occlusion and stenosis of cerebral arteries, not resulting in cerebral infarction (via I63.-), I67 — Other cerebrovascular diseases (via I63.-), P91.82 — Neonatal cerebral infarction (via I63.-).

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

Referenced by 3 Excludes2 notes: I10 — Essential (primary) hypertension (via I63.-), I15 — Secondary hypertension (via I63.-), I74 — Arterial embolism and thrombosis (via I63.-).

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

Referenced by 3 Code First instructions across 3 chapters: G46 — Vascular syndromes of brain in cerebrovascular diseases (via I63.-), R29.7 — National Institutes of Health Stroke Scale (NIHSS) score (via I63.-), Z92.82 — Status post administration of tPA (rtPA) in a different facility within the last 24 hours prior to admission to current facility (via I63.-).

Each of these codes carries a Code First note naming this condition — when that code is reported, THIS code is sequenced first, ahead of it.

Referenced by 11 Code Also instructions across 3 chapters: D57.03 — Hb-SS disease with cerebral vascular involvement (via I63.-), D57.213 — Sickle-cell/Hb-C disease with cerebral vascular involvement (via I63.-), D57.413 — Sickle-cell thalassemia, unspecified, with cerebral vascular involvement (via I63.-), D57.433 — Sickle-cell thalassemia beta zero with cerebral vascular involvement (via I63.-), D57.453 — Sickle-cell thalassemia beta plus with cerebral vascular involvement (via I63.-), D57.813 — Other sickle-cell disorders with cerebral vascular involvement (via I63.-), D81.32 — Adenosine deaminase 2 deficiency (via I63.-), G43.6 — Persistent migraine aura with cerebral infarction (via I63.-), G96.81 — Intracranial hypotension (via I63.-), I16.1 — Hypertensive emergency (via I63.-), I67.850 — Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (via I63.-).

These codes suggest coding this condition alongside when both are present.

MS-DRG Grouper Relationships (FY2027)

Potential MS-DRG participation — not a DRG assignment.

FY2027 MS-DRG: MCC — Major Complication or Comorbidity. Reported as a secondary diagnosis, this code raises the stay's MS-DRG severity tier — except when the principal diagnosis is one of 84 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 10 MS-DRGs: DRG 023 (MDC 01), DRG 024 (MDC 01), DRG 061 (MDC 01), DRG 062 (MDC 01), DRG 063 (MDC 01), DRG 064 (MDC 01), DRG 065 (MDC 01), DRG 066 (MDC 01), DRG 791 (MDC 15), DRG 793 (MDC 15).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):CIR020 — Cerebral infarction (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical process (MS-DRG)

Acts as MCC — raises the severity of other admissions. CMS groups these diagnoses into one MS-DRG principal-diagnosis exclusion process — a CC/MCC on this list never raises severity when the principal diagnosis is also on it.

I63.533 — Cerebral infarction due to unspecified occlusion or stenosis of bilateral posterior cerebral arteries, I63.539 — Cerebral infarction due to unspecified occlusion or stenosis of unspecified posterior cerebral artery, I63.541 — Cerebral infarction due to unspecified occlusion or stenosis of right cerebellar artery, I63.542 — Cerebral infarction due to unspecified occlusion or stenosis of left cerebellar artery, I63.543 — Cerebral infarction due to unspecified occlusion or stenosis of bilateral cerebellar arteries, I63.549 — Cerebral infarction due to unspecified occlusion or stenosis of unspecified cerebellar artery, I63.59 — Cerebral infarction due to unspecified occlusion or stenosis of other cerebral artery, I63.6 — Cerebral infarction due to cerebral venous thrombosis, nonpyogenic, I63.81 — Other cerebral infarction due to occlusion or stenosis of small artery, I63.89 — Other cerebral infarction, I66.01 — Occlusion and stenosis of right middle cerebral artery, I66.02 — Occlusion and stenosis of left middle cerebral artery, I66.03 — Occlusion and stenosis of bilateral middle cerebral arteries, I66.09 — Occlusion and stenosis of unspecified middle cerebral artery, I66.11 — Occlusion and stenosis of right anterior cerebral artery, I66.12 — Occlusion and stenosis of left anterior cerebral artery, I66.13 — Occlusion and stenosis of bilateral anterior cerebral arteries, I66.19 — Occlusion and stenosis of unspecified anterior cerebral artery, I66.21 — Occlusion and stenosis of right posterior cerebral artery, I66.22 — Occlusion and stenosis of left posterior cerebral artery, +63 more

Same CMS-HCC risk category (V28)

CMS maps these diagnoses to the same Hierarchical Condition Category (Ischemic or Unspecified Stroke) for risk-adjusted payment.

I63.521 — Cerebral infarction due to unspecified occlusion or stenosis of right anterior cerebral artery, I63.522 — Cerebral infarction due to unspecified occlusion or stenosis of left anterior cerebral artery, I63.523 — Cerebral infarction due to unspecified occlusion or stenosis of bilateral anterior cerebral arteries, I63.529 — Cerebral infarction due to unspecified occlusion or stenosis of unspecified anterior cerebral artery, I63.531 — Cerebral infarction due to unspecified occlusion or stenosis of right posterior cerebral artery, I63.532 — Cerebral infarction due to unspecified occlusion or stenosis of left posterior cerebral artery, I63.533 — Cerebral infarction due to unspecified occlusion or stenosis of bilateral posterior cerebral arteries, I63.539 — Cerebral infarction due to unspecified occlusion or stenosis of unspecified posterior cerebral artery, I63.541 — Cerebral infarction due to unspecified occlusion or stenosis of right cerebellar artery, I63.542 — Cerebral infarction due to unspecified occlusion or stenosis of left cerebellar artery, I63.543 — Cerebral infarction due to unspecified occlusion or stenosis of bilateral cerebellar arteries, I63.549 — Cerebral infarction due to unspecified occlusion or stenosis of unspecified cerebellar artery, I63.59 — Cerebral infarction due to unspecified occlusion or stenosis of other cerebral artery, I63.6 — Cerebral infarction due to cerebral venous thrombosis, nonpyogenic, I63.81 — Other cerebral infarction due to occlusion or stenosis of small artery, I63.89 — Other cerebral infarction, P91.821 — Neonatal cerebral infarction, right side of brain, P91.822 — Neonatal cerebral infarction, left side of brain, P91.823 — Neonatal cerebral infarction, bilateral, P91.829 — Neonatal cerebral infarction, unspecified side, +74 more

Related risk categories

These categories interact through CMS's HCC hierarchy — one can suppress the other's risk-adjustment weight when both are present on a claim.

Intracranial Hemorrhage

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Cerebral infarction).

I63.539 — Cerebral infarction due to unspecified occlusion or stenosis of unspecified posterior cerebral artery, I63.541 — Cerebral infarction due to unspecified occlusion or stenosis of right cerebellar artery, I63.542 — Cerebral infarction due to unspecified occlusion or stenosis of left cerebellar artery, I63.543 — Cerebral infarction due to unspecified occlusion or stenosis of bilateral cerebellar arteries, I63.549 — Cerebral infarction due to unspecified occlusion or stenosis of unspecified cerebellar artery, I63.59 — Cerebral infarction due to unspecified occlusion or stenosis of other cerebral artery, I63.6 — Cerebral infarction due to cerebral venous thrombosis, nonpyogenic, I63.8 — Other cerebral infarction, I63.81 — Other cerebral infarction due to occlusion or stenosis of small artery, I63.89 — Other cerebral infarction, I97.810 — Intraoperative cerebrovascular infarction during cardiac surgery, I97.811 — Intraoperative cerebrovascular infarction during other surgery, I97.820 — Postprocedural cerebrovascular infarction following cardiac surgery, I97.821 — Postprocedural cerebrovascular infarction following other surgery, R29.700 — NIHSS score 0, R29.701 — NIHSS score 1, R29.702 — NIHSS score 2, R29.703 — NIHSS score 3, R29.704 — NIHSS score 4, R29.705 — NIHSS score 5, +122 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main terms “Deficit”, “Infarct, infarction”; these codes share that main term but sit in a different category of the Tabular List.

I21.9 — Acute myocardial infarction, unspecified (myocardium, myocardial), I21.A1 — Myocardial infarction type 2 (myocardium, myocardial, type 2), I21.A9 — Other myocardial infarction type (myocardium, myocardial, type 5), I21.B — Myocardial infarction with coronary microvascular dysfunction (myocardium, myocardial, with, coronary microvascular disease), I22.0 — Subsequent ST elevation (STEMI) myocardial infarction of anterior wall (myocardium, myocardial, subsequent, anterior), I22.1 — Subsequent ST elevation (STEMI) myocardial infarction of inferior wall (myocardium, myocardial, subsequent, inferior), I22.2 — Subsequent non-ST elevation (NSTEMI) myocardial infarction (myocardium, myocardial, subsequent, subendocardial), I22.8 — Subsequent ST elevation (STEMI) myocardial infarction of other sites (myocardium, myocardial, subsequent, septal), I22.9 — Subsequent ST elevation (STEMI) myocardial infarction of unspecified site (myocardium, myocardial, subsequent), I25.2 — Old myocardial infarction (myocardium, myocardial, past), I69.010 — Attention and concentration deficit following nontraumatic subarachnoid hemorrhage (attention and concentration, following, nontraumatic, subarachnoid hemorrhage), I69.011 — Memory deficit following nontraumatic subarachnoid hemorrhage (memory, following, nontraumatic, subarachnoid hemorrhage), I69.012 — Visuospatial deficit and spatial neglect following nontraumatic subarachnoid hemorrhage (visuospatial, following, nontraumatic, subarachnoid hemorrhage), I69.013 — Psychomotor deficit following nontraumatic subarachnoid hemorrhage (psychomotor, following, nontraumatic, subarachnoid hemorrhage), I69.014 — Frontal lobe and executive function deficit following nontraumatic subarachnoid hemorrhage (frontal lobe, following, nontraumatic, subarachnoid hemorrhage), I69.015 — Cognitive social or emotional deficit following nontraumatic subarachnoid hemorrhage (cognitive, social, following, nontraumatic, subarachnoid hemorrhage), I69.018 — Other symptoms and signs involving cognitive functions following nontraumatic subarachnoid hemorrhage (cognitive NEC, following, nontraumatic, subarachnoid hemorrhage), I69.019 — Unspecified symptoms and signs involving cognitive functions following nontraumatic subarachnoid hemorrhage (cognitive, following, nontraumatic, subarachnoid hemorrhage), I69.110 — Attention and concentration deficit following nontraumatic intracerebral hemorrhage (attention and concentration, following, nontraumatic, intracerebral hemorrhage), I69.111 — Memory deficit following nontraumatic intracerebral hemorrhage (memory, following, nontraumatic, intracerebral hemorrhage), +105 more

Lab tests where this diagnosis supports Medicare coverage (NCD)

Medicare's National Coverage Determination (NCD) program lists this diagnosis as medical justification for these lab tests.

Lipid Panel, Partial Thromboplastin Time (PTT) Test, Prothrombin Time Test and INR (PT/INR)

Contextual Map

Every relationship of I63.9 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run I63.9 with these 20 related codes in Claim Check

Hierarchy

Excludes2

Referenced by Excludes1 notes

Referenced by Excludes2 notes

  • I10 — Essential (primary) hypertension[Excludes2](via I63.-): “essential (primary) hypertension involving vessels of brain (I60-I69)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • I15 — Secondary hypertension[Excludes2](via I63.-): “secondary hypertension involving vessels of brain (I60-I69)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • I74 — Arterial embolism and thrombosis[Excludes2](via I63.-): “basilar embolism and thrombosis (I63.0-I63.2, I65.1)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Code First instructions

Referenced by Code Also instructions (11)

Clinical classification (CCSR)

Risk adjustment (CMS-HCC)

  • HCC 249 — Ischemic or Unspecified Stroke [CMS-HCC]— CMS-HCC V28 · 2026

MS-DRG Grouper (10)

MDC crossing

  • MDC 01 — Diseases and Disorders of the Nervous System[MDC crossing]: “Diseases and Disorders of the Nervous System — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 8,919 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2027

Index entries (16)

  • Accident, cerebrovascular (ischemic)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Accident, cerebrovascular (ischemic), aborted[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Accident, craniovascular[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Accident, vascular, brain[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Deficit, neurologic NEC, ischemic, reversible (RIND)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Deficit, neurologic NEC, ischemic, reversible (RIND), prolonged (PRIND)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Deficit, prolonged reversible ischemic neurologic (PRIND)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Infarct, infarction, cerebral (acute), aborted[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • and 8 more

Nearest codes (40)

Change history

  • FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Common coding questions

Is I63.9 the code for “history of stroke”?

No — I63.9 reports the acute cerebral infarction itself (“Stroke NOS” is its inclusion term). For a later encounter focused on the history of the infarction or its residual effects rather than the current acute infarction, the code’s own Excludes2 notes point two ways: Z86.73 when no deficits remain, or an I69.3- sequela code for the residuals. The split is walked in the sequela guide.

What additional codes does I63.9 ask for?

Its Use Additional Code note is long and concrete: tPA administered within the prior 24 hours at another facility (Z92.82), the NIHSS score (R29.7-), and documented contributors — hypertension (I10–I1A), tobacco dependence or use (F17.-, Z72.0), alcohol abuse and dependence (F10.-), and the exposure codes.

Is a TIA coded with I63.9?

No — transient cerebral ischemic attacks and related syndromes are an Excludes2 routing to G45.-. A TIA that resolves without infarction is reported with the G45 code for that encounter.

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data
CMS/CDC ICD-10-CM FY2027 tabular list, index and tables, effective October 1, 2026 Release, file and checksum · Publisher’s page
Coding guidelines Official source data
ICD-10-CM Official Guidelines for Coding and Reporting (FY2027), quoted by section Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v44.0 (October 2026) Release, file and checksum · Publisher’s page
Inpatient payment groups Official source data
CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v44 Release, file and checksum · Publisher’s page
Risk adjustment Official source data
2026 Mid-Year Final ICD-10 Mappings + Model Software (cms.gov/files/zip/2026-midyear-final-icd-10-mappings.zip, 2026-midyear-final-model-software.zip) — CMS-HCC V28, PY2026 mid-year final release Release, file and checksum · Publisher’s page
Change history and date-of-service validity Official source data
CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page
Comparisons, relationships and the contextual map MedCoder structured relationship
Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears
Summary, coding notes, decision checklist and FAQ answers MedCoder explanation
Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "I63.9 — Cerebral infarction, unspecified." ICD-10-CM FY2027. https://medcoder.ai/icd10/code/i63.9-cerebral-infarction-unspecified

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Cerebral infarction, unspecified

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027, and none are recorded for this code. Note changes are tracked from FY2027 only.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to I63.9 in its code family, with their registry titles.

View all codes in the I63 family