ICD-10-CM 2027 diagnosis code
G35.BPrimary progressive multiple sclerosis
G35.B is a header code, so it can't be reported by itself. Choose one of the 3 more specific codes beneath it.
Code last changed in FY2026 (effective October 1, 2025). Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data
About G35.B
G35.B is the ICD-10-CM diagnosis code for primary progressive multiple sclerosis. It belongs to category G35 (multiple sclerosis), block G35-G37 (demyelinating diseases of the central nervous system) and chapter 6 (diseases of the nervous system). It is a header code, so it can't be reported by itself; one of its 3 subcodes must be used instead.
Within G35 (multiple sclerosis), G35.B is specifically for primary progressive multiple sclerosis. Related codes cover Relapsing-remitting multiple sclerosis (G35.A), secondary progressive multiple sclerosis (G35.C) and unspecified (G35.D).
To report this condition, pick the subcode that matches the documentation: G35.B0 (unspecified), G35.B1 (sclerosis) and G35.B2 (sclerosis).
It was added in FY2026, effective October 1, 2025.
Specific codes under G35.B
Notes that apply from higher levels
Instructions written at a parent level also apply to G35.B.
Broader instructions also apply from Chapter 6: Diseases of the nervous system.
Code history
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
- 2027
- FY2026 (effective 10/1/2025): Added
- No changes since FY2026.
Common questions about G35.B
Is G35.B billable?
- No. G35.B is a header code. Report one of its more specific subcodes instead.