ICD-10 Code for Multiple Sclerosis: Complete 2026 Guide
Complete reference for ICD-10 codes for multiple sclerosis (G35) including the 2026 subcategory codes for RRMS, PPMS, and SPMS with documentation and billing requirements.
Quick Reference: MS ICD-10 Codes
Table of Contents
Multiple Sclerosis ICD-10 Code Overview
Multiple sclerosis (MS) is a chronic autoimmune disease affecting the central nervous system, where the immune system attacks the protective myelin sheath covering nerve fibers. The primary ICD-10-CM code for MS is G35, which falls under Chapter 6: Diseases of the Nervous System (G00-G99).
MS affects approximately 2.8 million people worldwide and is one of the most common neurological conditions causing disability in young adults. Accurate coding is essential for treatment planning, research, and appropriate reimbursement.
Code Location in ICD-10-CM
2026 ICD-10 Updates for Multiple Sclerosis
Major Coding Change Alert
Effective October 1, 2025, the ICD-10-CM introduced one of the most significant expansions to MS coding since 2015. Previously, all MS types were captured under a single code (G35). The new subcategory codes allow for precise disease course documentation.
Key Changes:
- G35 is now a parent code - use subcategories for billing
- New codes distinguish RRMS, PPMS, and SPMS
- Active vs non-active disease status can now be captured
- HCC risk adjustment now reflects MS specificity
Claims Submission Requirement
Claims submitted with only G35 (without subcategory) for encounters on or after October 1, 2025 may be rejected. Ensure proper subcategory code selection based on documented MS type and disease activity.
Complete MS Subcategory Codes
Relapsing-Remitting Multiple Sclerosis (RRMS)
The most common form of MS, characterized by clearly defined relapses (attacks) followed by periods of partial or complete recovery (remissions).
Prevalence: Approximately 85% of initial MS diagnoses
Primary Progressive MS, Unspecified
Steady worsening of neurologic function from onset without distinct relapses, activity status not specified.
Prevalence: Approximately 10-15% of MS patients
Active Primary Progressive MS
Primary progressive MS with evidence of new MRI activity, clinical relapses, or disease progression requiring therapeutic intervention.
Prevalence: Subset of PPMS patients
Non-Active Primary Progressive MS
Primary progressive MS that is stable without recent clinical relapses or new imaging changes.
Prevalence: Subset of PPMS patients
Secondary Progressive MS, Unspecified
MS that has transitioned from relapsing-remitting to progressive disease, activity status not specified.
Prevalence: Many RRMS patients transition after ~10 years
Active Secondary Progressive MS
Secondary progressive MS with ongoing disease activity (relapses, new MRI lesions, or progression).
Prevalence: Subset of SPMS patients
Non-Active Secondary Progressive MS
Secondary progressive MS without recent clinical activity or new imaging findings.
Prevalence: Subset of SPMS patients
Multiple Sclerosis, Unspecified
Use when the specific MS type or disease course is not documented or cannot be determined.
Prevalence: Should be minimized with proper documentation
Understanding Active vs Non-Active MS Codes
Active MS (B1, C1)
Indicates ongoing disease activity requiring monitoring or intervention.
- Clinical relapses within past year
- New or enlarging lesions on MRI
- Gadolinium-enhancing lesions
- Disease progression requiring treatment change
Non-Active MS (B2, C2)
Indicates disease stability without recent activity.
- No relapses in past 12 months
- Stable MRI without new lesions
- Stable neurological examination
- Current treatment maintaining remission
Associated ICD-10 Codes for MS Manifestations
MS often presents with multiple symptoms and complications. Use these additional codes to fully capture the patient's condition and support appropriate reimbursement.
| Code | Description | When to Use |
|---|---|---|
| H46 | Optic neuritis (common MS manifestation) | Optic nerve inflammation |
| H46.11 | Retrobulbar neuritis, right eye | Right-sided optic neuritis |
| H46.12 | Retrobulbar neuritis, left eye | Left-sided optic neuritis |
| G89.29 | Other chronic pain | Neuropathic pain from MS |
| M62.81 | Muscle weakness (generalized) | MS-related muscle weakness |
| N31.9 | Neuromuscular dysfunction of bladder | Neurogenic bladder dysfunction |
| R26.2 | Difficulty in walking, NEC | Gait disturbances |
| R27.0 | Ataxia, unspecified | Cerebellar involvement |
| R20.2 | Paresthesia of skin | Numbness/tingling sensations |
| G24.02 | Drug induced dystonia | Spasticity/muscle rigidity |
| R53.83 | Other fatigue | MS-related fatigue |
| F06.32 | Mood disorder due to known condition, with major depressive-like episode | Depression secondary to MS |
| R47.1 | Dysarthria and anarthria | Speech difficulties |
| H53.2 | Diplopia | Double vision |
Documentation Requirements for MS Coding
Essential Documentation Elements
Disease Course Documentation
- • MS type (RRMS, PPMS, SPMS)
- • Disease activity status (active/non-active)
- • Date of diagnosis
- • Disease progression history
- • Transition from RRMS to SPMS if applicable
Clinical Findings
- • Current symptoms and severity
- • Recent relapses with dates
- • EDSS score (Expanded Disability Status Scale)
- • MRI findings with dates
- • Current treatments and response
McDonald Criteria Documentation
For initial diagnosis, document evidence supporting the 2024 McDonald criteria:
- • Dissemination in Space (DIS): Lesions in 2+ CNS regions (optic nerve, cortical, periventricular, infratentorial, spinal cord)
- • Dissemination in Time (DIT): Evidence of activity at different time points (or may be waived per 2024 criteria)
- • CSF findings: Oligoclonal bands or elevated kappa free light chains
- • Exclusion of alternatives: Other diagnoses ruled out
Clinical Manifestations to Document
Visual
- • Optic neuritis
- • Diplopia
- • Nystagmus
Motor
- • Weakness
- • Spasticity
- • Gait disturbance
Sensory
- • Paresthesias
- • Lhermitte's sign
- • Uhthoff's phenomenon
Cerebellar
- • Ataxia
- • Tremor
- • Dysarthria
Autonomic
- • Bladder dysfunction
- • Bowel dysfunction
- • Sexual dysfunction
Cognitive/Psych
- • Fatigue
- • Depression
- • Cognitive impairment
Billing Guidelines for MS Codes
MS-DRG Classification (Inpatient)
For inpatient stays, MS codes map to three possible DRG groupings (MS-DRG Version 42.0, effective April 2025):
| DRG | Description | Reimbursement |
|---|---|---|
| 058 | Multiple sclerosis and cerebellar ataxia with MCC | Higher reimbursement |
| 059 | Multiple sclerosis and cerebellar ataxia with CC | Moderate reimbursement |
| 060 | Multiple sclerosis and cerebellar ataxia without CC/MCC | Base reimbursement |
MCC = Major Complication/Comorbidity, CC = Complication/Comorbidity
Risk Adjustment (HCC)
MS codes carry Hierarchical Condition Category (HCC) risk adjustment value, affecting:
- • Risk Adjustment Factor (RAF) scores
- • Medicare Advantage capitation
- • Value-based care calculations
Primary Diagnosis Use
G35 subcategory codes are appropriate as:
- • First-listed (primary) diagnosis
- • Principal diagnosis for inpatient stays
- • Secondary diagnosis with other conditions
Accurate MS Coding Made Easy
PatientNotes AI automatically captures MS type, disease activity, and clinical manifestations during patient visits. Generate complete documentation that supports accurate ICD-10 coding every time.
Start Free TrialFrequently Asked Questions
What is the ICD-10 code for multiple sclerosis?
The primary ICD-10 code for multiple sclerosis is G35. Starting October 1, 2025, new subcategory codes were introduced: G35.A for relapsing-remitting MS, G35.B for primary progressive MS, G35.C for secondary progressive MS, and G35.D for unspecified MS.
What are the new ICD-10 codes for MS in 2026?
The 2026 ICD-10-CM includes expanded MS codes: G35.A (relapsing-remitting MS), G35.B0/B1/B2 (primary progressive MS - unspecified/active/non-active), G35.C0/C1/C2 (secondary progressive MS - unspecified/active/non-active), and G35.D (unspecified MS). These allow for more precise disease course documentation.
Is G35 billable for multiple sclerosis?
As of October 2025, G35 alone is no longer recommended for billing. Use the specific subcategory codes (G35.A, G35.B0-B2, G35.C0-C2, or G35.D) to ensure proper reimbursement and accurate disease classification.
What is the difference between active and non-active MS codes?
Active MS (G35.B1, G35.C1) indicates clinical relapses, new MRI activity, or disease progression requiring therapeutic intervention. Non-active MS (G35.B2, G35.C2) indicates disease stability without recent relapses or new imaging changes.
What additional ICD-10 codes should be used with MS?
Common additional codes used with MS include: H46 for optic neuritis, G89.29 for chronic neuropathic pain, M62.81 for MS-related muscle weakness, N31.9 for neurogenic bladder, R26.2 for difficulty walking, and F06.32 for depression secondary to MS.