ICD-10-CM 2027 diagnosis code
I67.5Moyamoya disease
I67.5 is a valid, billable ICD-10-CM code for moyamoya disease. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.
Looking up by condition? See ICD-10 code for Nishimoto disease, ICD-10 code for Encephaloduroarteriomyosynangiosis.
Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data
About I67.5
I67.5 is the ICD-10-CM diagnosis code for Moyamoya disease. It belongs to category I67 (other cerebrovascular diseases), block I60-I69 (cerebrovascular diseases) and chapter 9 (diseases of the circulatory system). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.
Within I67 (other cerebrovascular diseases), I67.5 is specifically for Moyamoya disease. Related codes cover dissection of cerebral arteries, nonruptured (I67.0), cerebral aneurysm, nonruptured (I67.1), cerebral atherosclerosis (I67.2), progressive vascular leukoencephalopathy (I67.3), hypertensive encephalopathy (I67.4), nonpyogenic thrombosis of intracranial venous system (I67.6), cerebral arteritis, not elsewhere classified (I67.7), other specified cerebrovascular diseases (I67.8) and 1 more.
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 091 (Other Disorders of Nervous System with MCC, relative weight 1.7046), DRG 092 (Other Disorders of Nervous System with CC, relative weight 1.0239) and DRG 093 (Other Disorders of Nervous System without CC/MCC, relative weight 0.7783), in MDC 01 (Diseases and Disorders of the Nervous 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 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 437.5 (Moyamoya disease).
Notes that apply from higher levels
Instructions written at a parent level also apply to I67.5.
Broader instructions also apply from I60-I69 Cerebrovascular diseases and Chapter 9: Diseases of the circulatory system.
Alphabetic index entries
5 entriesTerms in the official ICD-10-CM index that lead to I67.5.
MS-DRG v44.0 grouping
All DRGs →Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.
MDC 01 · Diseases and Disorders of the Nervous System
ICD-9-CM equivalent
Converter →- 437.5Moyamoya diseaseexact
From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.
Code history
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
- 2027
- FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
- No changes since FY2016.
Common questions about I67.5
Is I67.5 billable?
- Yes. I67.5 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can I67.5 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict I67.5 as a principal diagnosis.
Is I67.5 a CC or MCC?
- I67.5 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.
What DRG does I67.5 group to?
- I67.5 is used in the MS-DRG v44.0 logic for MS-DRG 091 (Other Disorders of Nervous System with MCC), MS-DRG 092 (Other Disorders of Nervous System with CC) and MS-DRG 093 (Other Disorders of Nervous System without CC/MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.
What is the ICD-9 code for I67.5?
- The CMS General Equivalence Mappings map I67.5 to ICD-9-CM 437.5.