On October 1, 2025, ICD-10-CM updates took effect, introducing major coding changes for Multiple Sclerosis (MS), a chronic, progressive neurological condition affecting nearly 1 million people in the United States, and is one of the most commonly known neurological conditions. Until now, ICD-10-CM coding for MS lacked the specificity needed to capture disease severity, activity, and treatment decisions. This gap created challenges for documentation, risk adjustment, and reimbursement. The 2025 update marks a milestone—bringing coding into alignment with clinical practice and integrated patient care.
For providers, coders, and revenue cycle teams, these updates are more than just a coding change; they reflect evolving clinical understanding and the critical role of integrated neurology and behavioral health management.
MS is a neurological disease in which the immune system attacks the protective sheath covering nerve fibers (known as myelin), disrupting communication between the brain and the rest of the body. Symptoms vary widely but often include fatigue, numbness, muscle weakness, vision problems, and mobility challenges.
Beyond the physiological symptoms, cognitive impairment and mental health challenges are common among patients with MS, affecting up to 65% of patients. Memory loss, slowed processing speed, difficulty concentrating, and depression resulting from MS can significantly reduce quality of life. Without structured assessment, cognitive and mood changes may be overlooked, limiting early interventions and leaving documentation and risk-adjusted reimbursement incomplete.
Given its complexity, MS is increasingly recognized not just as a physical disease but as one requiring integrated neurological and behavioral health management. Accurate coding reflecting both disease activity and cognitive impact is essential, not only for patient care but for ensuring documentation supports proper reimbursement, care coordination, and quality reporting.
The 2025 ICD-10-CM update introduces major revisions to Multiple Sclerosis (MS) coding, representing one of the most significant expansions in recent years.
Since ICD-10-CM was implemented in 2015, MS has been captured by a single code (G35) with no further distinctions. Beginning October 1, 2025, the MS code category will expand into detailed subcategories, allowing clinicians and coders to capture disease course with greater precision:
These refinements enable more precise documentation of disease trajectory and treatment response—supporting care planning, quality reporting, and reimbursement integrity.
Coding specificity is more than just an administrative detail; it directly impacts patient care, reporting accuracy, and reimbursement.
Consider a patient initially diagnosed with relapsing-remitting MS (G35.A). Years later, they transition to secondary progressive MS, active (G35.C1). Previously, both stages would have been coded simply as G35, masking disease progression and potentially affecting treatment decisions and reimbursement. With the updated codes, the disease trajectory is captured accurately, ensuring alignment across clinical care, research, and funding.
MS affects more than mobility and motor function. Cognitive changes and comorbid mood disorders may appear early—sometimes even before physical decline—and can progress silently. Without structured assessment, these symptoms may go undetected, delaying tailored support and targeted interventions, resulting in incomplete documentation and missed reimbursement opportunities tied to risk adjustment.
Early detection can change care trajectories. Identifying slowed processing, memory lapses, or diminished concentration early allows providers to deliver tailored, adaptive treatment plans for an often-overlooked aspect of MS care.
When integrated early in the care workflow, Creyos enables neurology and behavioral health teams to provide:
By uncovering and monitoring cognitive changes that often go unnoticed, Creyos helps care teams intervene sooner and more precisely—while ensuring coding accurately reflects patient complexity and supports reimbursement.
To ensure readiness, providers and coders should:
The October 2025 ICD-10-CM updates for Multiple Sclerosis (MS) reflect the growing recognition that MS impacts both physical and cognitive health. More precise coding, combined with structured cognitive and behavioral health assessments, enables providers to deliver better-informed care while safeguarding reimbursement integrity.
The dual benefit is clear:
With tools like Creyos, clinicians can confidently implement these changes, ensuring patients with MS receive proactive, coordinated care while documentation and coding fully reflect their complexity.
Written by Emily Montemayor, Medical Coding Support Manager at Creyos
Emily Montemayor, a CCS, COC, CPC, CPMA, CMBCS, QMRAC, CPC-I, CPA-EDU Approved Instructor, is a recognized expert in coding compliance, revenue integrity, and provider education. As Medical Coding Support Manager at Creyos and Director of Education for OAHIMA, she has led international training and initiatives that optimize reimbursement, enhance documentation, and advance coding practices—driven by her passion for empowering healthcare teams and improving patient care through education and compliance excellence.