ICD-10 Code G35.B0 – Primary progressive multiple sclerosis, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G35.B0 – Primary progressive multiple sclerosis, unspecified
What it is
This code identifies primary progressive multiple sclerosis when the record does not specify a more detailed subtype. It describes a chronic demyelinating disease with steady neurologic worsening from onset.
Clinical signs
Clinical features vary; refer to documentation. Common findings include gradually progressive weakness, spasticity, gait difficulty, balance problems, and other neurologic deficits without clear relapses.
When to use this code
Use G35.B0 when the provider documents primary progressive multiple sclerosis but does not identify a more specific form. It also fits when the chart confirms progressive disease from onset and the subtype remains unspecified. Check documentation if the note suggests relapsing activity or another MS pattern.
Do not use for
Do not use this code for relapsing-remitting, secondary progressive, or clinically isolated syndromes. If the documentation names a different MS subtype, code that condition instead.
Coding tip
Code only what is documented; if “primary progressive” is not stated, verify the provider’s wording before assigning G35.B0.