MS-DRG · FY 2026 v43.0

MS-DRG 66 – Intracranial Hemorrhage or Cerebral Infarction without CC/MCC

A Medical DRG in MDC 01 (Diseases & Disorders of the Nervous System). Inpatient cases group to DRG 66 when the ICD-10-CM principal diagnosis is one of the 124 codes listed below and no secondary diagnosis on the CC or MCC lists is present. Its FY 2026 relative weight is 0.6844 with a geometric mean length of stay of 1.9 days.

Medical DRG – assigned by principal diagnosis✓ Official CMS v43.0 dataset
0.6844
Relative Weight
1.9
Geometric Mean LOS (days)
2.3
Arithmetic Mean LOS (days)
124
Principal Diagnosis Codes
How a case is assigned to DRG 66

The grouper first assigns the case to MDC 01 from the principal diagnosis and finds no qualifying operating-room procedure (this is a Medical DRG; ICD-10-PCS codes do not drive assignment here).

ICD-10-CM

Principal Diagnosis Codes 124 codes · 4 categories

124 of 124 shown
I60 Nontraumatic subarachnoid hemorrhage18 codes
  • I60.00 Nontraumatic subarachnoid hemorrhage from unspecified carotid siphon and bifurcation
  • I60.01 Nontraumatic subarachnoid hemorrhage from right carotid siphon and bifurcation
  • I60.02 Nontraumatic subarachnoid hemorrhage from left carotid siphon and bifurcation
  • I60.10 Nontraumatic subarachnoid hemorrhage from unspecified middle cerebral artery
  • I60.11 Nontraumatic subarachnoid hemorrhage from right middle cerebral artery
  • I60.12 Nontraumatic subarachnoid hemorrhage from left middle cerebral artery
  • I60.2 Nontraumatic subarachnoid hemorrhage from anterior communicating artery
  • I60.30 Nontraumatic subarachnoid hemorrhage from unspecified posterior communicating artery
  • I60.31 Nontraumatic subarachnoid hemorrhage from right posterior communicating artery
  • I60.32 Nontraumatic subarachnoid hemorrhage from left posterior communicating artery
  • I60.4 Nontraumatic subarachnoid hemorrhage from basilar artery
  • I60.50 Nontraumatic subarachnoid hemorrhage from unspecified vertebral artery
  • I60.51 Nontraumatic subarachnoid hemorrhage from right vertebral artery
  • I60.52 Nontraumatic subarachnoid hemorrhage from left vertebral artery
  • I60.6 Nontraumatic subarachnoid hemorrhage from other intracranial arteries
  • I60.7 Nontraumatic subarachnoid hemorrhage from unspecified intracranial artery
  • I60.8 Other nontraumatic subarachnoid hemorrhage
  • I60.9 Nontraumatic subarachnoid hemorrhage, unspecified
I61 Nontraumatic intracerebral hemorrhage9 codes
  • I61.0 Nontraumatic intracerebral hemorrhage in hemisphere, subcortical
  • I61.1 Nontraumatic intracerebral hemorrhage in hemisphere, cortical
  • I61.2 Nontraumatic intracerebral hemorrhage in hemisphere, unspecified
  • I61.3 Nontraumatic intracerebral hemorrhage in brain stem
  • I61.4 Nontraumatic intracerebral hemorrhage in cerebellum
  • I61.5 Nontraumatic intracerebral hemorrhage, intraventricular
  • I61.6 Nontraumatic intracerebral hemorrhage, multiple localized
  • I61.8 Other nontraumatic intracerebral hemorrhage
  • I61.9 Nontraumatic intracerebral hemorrhage, unspecified
I62 Other and unspecified nontraumatic intracranial hemorrhage6 codes
  • I62.00 Nontraumatic subdural hemorrhage, unspecified
  • I62.01 Nontraumatic acute subdural hemorrhage
  • I62.02 Nontraumatic subacute subdural hemorrhage
  • I62.03 Nontraumatic chronic subdural hemorrhage
  • I62.1 Nontraumatic extradural hemorrhage
  • I62.9 Nontraumatic intracranial hemorrhage, unspecified
I63 Cerebral infarction91 codes
  • I63.00 Cerebral infarction due to thrombosis of unspecified precerebral artery
  • I63.011 Cerebral infarction due to thrombosis of right vertebral artery
  • I63.012 Cerebral infarction due to thrombosis of left vertebral artery
  • I63.013 Cerebral infarction due to thrombosis of bilateral vertebral arteries
  • I63.019 Cerebral infarction due to thrombosis of unspecified vertebral artery
  • I63.02 Cerebral infarction due to thrombosis of basilar artery
  • I63.031 Cerebral infarction due to thrombosis of right carotid artery
  • I63.032 Cerebral infarction due to thrombosis of left carotid artery
  • I63.033 Cerebral infarction due to thrombosis of bilateral carotid arteries
  • I63.039 Cerebral infarction due to thrombosis of unspecified carotid artery
  • I63.09 Cerebral infarction due to thrombosis of other precerebral artery
  • I63.10 Cerebral infarction due to embolism of unspecified precerebral artery
  • I63.111 Cerebral infarction due to embolism of right vertebral artery
  • I63.112 Cerebral infarction due to embolism of left vertebral artery
  • I63.113 Cerebral infarction due to embolism of bilateral vertebral arteries
  • I63.119 Cerebral infarction due to embolism of unspecified vertebral artery
  • I63.12 Cerebral infarction due to embolism of basilar artery
  • I63.131 Cerebral infarction due to embolism of right carotid artery
  • I63.132 Cerebral infarction due to embolism of left carotid artery
  • I63.133 Cerebral infarction due to embolism of bilateral carotid arteries
  • I63.139 Cerebral infarction due to embolism of unspecified carotid artery
  • I63.19 Cerebral infarction due to embolism of other precerebral artery
  • I63.20 Cerebral infarction due to unspecified occlusion or stenosis of unspecified precerebral arteries
  • I63.211 Cerebral infarction due to unspecified occlusion or stenosis of right vertebral artery
  • I63.212 Cerebral infarction due to unspecified occlusion or stenosis of left vertebral artery
  • I63.213 Cerebral infarction due to unspecified occlusion or stenosis of bilateral vertebral arteries
  • I63.219 Cerebral infarction due to unspecified occlusion or stenosis of unspecified vertebral artery
  • I63.22 Cerebral infarction due to unspecified occlusion or stenosis of basilar artery
  • I63.231 Cerebral infarction due to unspecified occlusion or stenosis of right carotid arteries
  • I63.232 Cerebral infarction due to unspecified occlusion or stenosis of left carotid arteries
  • I63.233 Cerebral infarction due to unspecified occlusion or stenosis of bilateral carotid arteries
  • I63.239 Cerebral infarction due to unspecified occlusion or stenosis of unspecified carotid artery
  • I63.29 Cerebral infarction due to unspecified occlusion or stenosis of other precerebral arteries
  • I63.30 Cerebral infarction due to thrombosis of unspecified cerebral artery
  • I63.311 Cerebral infarction due to thrombosis of right middle cerebral artery
  • I63.312 Cerebral infarction due to thrombosis of left middle cerebral artery
  • I63.313 Cerebral infarction due to thrombosis of bilateral middle cerebral arteries
  • I63.319 Cerebral infarction due to thrombosis of unspecified middle cerebral artery
  • I63.321 Cerebral infarction due to thrombosis of right anterior cerebral artery
  • I63.322 Cerebral infarction due to thrombosis of left anterior cerebral artery
  • I63.323 Cerebral infarction due to thrombosis of bilateral anterior cerebral arteries
  • I63.329 Cerebral infarction due to thrombosis of unspecified anterior cerebral artery
  • I63.331 Cerebral infarction due to thrombosis of right posterior cerebral artery
  • I63.332 Cerebral infarction due to thrombosis of left posterior cerebral artery
  • I63.333 Cerebral infarction due to thrombosis of bilateral posterior cerebral arteries
  • I63.339 Cerebral infarction due to thrombosis of unspecified posterior cerebral artery
  • I63.341 Cerebral infarction due to thrombosis of right cerebellar artery
  • I63.342 Cerebral infarction due to thrombosis of left cerebellar artery
  • I63.343 Cerebral infarction due to thrombosis of bilateral cerebellar arteries
  • I63.349 Cerebral infarction due to thrombosis of unspecified cerebellar artery
  • I63.39 Cerebral infarction due to thrombosis of other cerebral artery
  • I63.40 Cerebral infarction due to embolism of unspecified cerebral artery
  • I63.411 Cerebral infarction due to embolism of right middle cerebral artery
  • I63.412 Cerebral infarction due to embolism of left middle cerebral artery
  • I63.413 Cerebral infarction due to embolism of bilateral middle cerebral arteries
  • I63.419 Cerebral infarction due to embolism of unspecified middle cerebral artery
  • I63.421 Cerebral infarction due to embolism of right anterior cerebral artery
  • I63.422 Cerebral infarction due to embolism of left anterior cerebral artery
  • I63.423 Cerebral infarction due to embolism of bilateral anterior cerebral arteries
  • I63.429 Cerebral infarction due to embolism of unspecified anterior cerebral artery
  • I63.431 Cerebral infarction due to embolism of right posterior cerebral artery
  • I63.432 Cerebral infarction due to embolism of left posterior cerebral artery
  • I63.433 Cerebral infarction due to embolism of bilateral posterior cerebral arteries
  • I63.439 Cerebral infarction due to embolism of unspecified posterior cerebral artery
  • I63.441 Cerebral infarction due to embolism of right cerebellar artery
  • I63.442 Cerebral infarction due to embolism of left cerebellar artery
  • I63.443 Cerebral infarction due to embolism of bilateral cerebellar arteries
  • I63.449 Cerebral infarction due to embolism of unspecified cerebellar artery
  • I63.49 Cerebral infarction due to embolism of other cerebral artery
  • I63.50 Cerebral infarction due to unspecified occlusion or stenosis of unspecified cerebral artery
  • I63.511 Cerebral infarction due to unspecified occlusion or stenosis of right middle cerebral artery
  • I63.512 Cerebral infarction due to unspecified occlusion or stenosis of left middle cerebral artery
  • I63.513 Cerebral infarction due to unspecified occlusion or stenosis of bilateral middle cerebral arteries
  • I63.519 Cerebral infarction due to unspecified occlusion or stenosis of unspecified middle cerebral artery
  • 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
  • I63.9 Cerebral infarction, unspecified
ICD-10-PCS

Procedure Codes

Procedure codes do not drive assignment for this DRG. DRG 66 is a Medical DRG, assigned from the principal diagnosis above.

Frequently Asked Questions

What is MS-DRG 66?

MS-DRG 66 (Intracranial Hemorrhage or Cerebral Infarction without CC/MCC) is a medical DRG in MDC 01 (Diseases & Disorders of the Nervous System). Its FY 2026 relative weight is 0.6844 with a geometric mean length of stay of 1.9 days.

How many diagnosis codes group to DRG 66?

124 ICD-10-CM principal diagnosis codes group to this DRG, spanning 4 three-character categories.

What is the relative weight of DRG 66?

The FY 2026 relative weight of this DRG is 0.6844, meaning reimbursement of roughly 0.68 times the average Medicare inpatient case. Multiply by a hospital's blended base rate for the approximate payment.

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Source: CMS ICD-10 MS-DRG v43.0 Definitions Manual and the FY 2026 IPPS Final Rule (Table 5), effective October 1, 2025 through September 30, 2026. We publish the DRG assignments as CMS defines them and add the navigation, search, and code links.