ICD-10 Code G35.C0 – Secondary progressive multiple sclerosis, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G35.C0 – Secondary progressive multiple sclerosis, unspecified
What it is
This code identifies secondary progressive multiple sclerosis when the record does not specify additional details. It represents a later MS course with gradual worsening after an earlier relapsing pattern.
Clinical signs
Clinical features vary; refer to documentation. Commonly, you may see progressive neurologic decline, such as increasing weakness, spasticity, gait difficulty, or functional loss, with or without prior relapses.
When to use this code
Use this code when the provider documents secondary progressive multiple sclerosis and does not specify a more detailed subtype. Apply it for established MS cases showing progression over time rather than a purely relapsing course.
If the record only says “multiple sclerosis” or the course is unclear, check documentation before assigning G35.C0. Use the documented diagnosis, not assumptions based on symptoms alone.
Do not use for
Do not use this code for relapsing-remitting, primary progressive, or unspecified multiple sclerosis without secondary progressive documentation. Check documentation if the record uses another MS subtype.
Coding tip
Confirm that the provider explicitly documents secondary progressive MS and note any more specific MS subtype before coding.