Cosponsored by the
The new revisions were created through a formal consensus process by 56 global experts across neurology, radiology, methodology, epidemiology, and patient advocacy. Patient representatives contributed to ensure the updates reflected both scientific advances and the lived experience of individuals living with MS. Since their introduction, the McDonald Diagnostic Criteria have reduced the average time from first symptoms to confirmed diagnosis by about 75%, dropping from roughly 4 years to 1 year in recent studies.
“These revisions represent an important step forward for the field,” neurologist Bruno Stankoff, MD, PhD, a professor of neurology at Sorbonne-Université in Paris and the president at ECTRIMS, in a statement.1 “By integrating novel biomarkers and rigorous consensus methodology, the updated criteria strengthen diagnostic accuracy and become more globally applicable. This balance between sensitivity and specificity is essential — and now ensures that people with MS can be identified earlier, equally across all ages, and that misdiagnosis is reduced.”
The 2024 revisions for diagnosing MS emphasize accessibility, integrating information on diagnostic tools that are more widely available and less invasive, which could support adoption across diverse clinical settings. According to ECTRIMS, these latest changes do not affect existing diagnoses but may help guide future diagnostic assessments to help clinicians identify MS earlier and reduce misdiagnosis.
READ MORE:
Among the key updates, the optic nerve has been recognized as a fifth topographical area of the central nervous system for demonstrating dissemination in space, reflecting the importance of visual pathway involvement in MS. The revisions also accept kappa free light chain (KFLC) testing as an alternative to the traditional use of oligoclonal bands for demonstrating dissemination in time, offering a less invasive and more accessible biomarker option.
Novel MRI biomarkers, including the central vein sign (CVS) and paramagnetic rim lesions (PRLs), are also acknowledged as supportive evidence in specific diagnostic situations. These MRI features have shown promise in distinguishing MS lesions from other causes of central nervous system inflammation, providing clinicians with additional tools to refine diagnostic accuracy. The guidelines also describe a biological diagnosis, which allows individuals with typical MRI findings and additional supportive evidence to meet diagnostic criteria even before symptoms appear.
Specialized criteria have been introduced for children, older adults, and individuals with vascular risk factors, groups that often present with diagnostic challenges because of overlapping symptoms or comorbidities. By tailoring the diagnostic framework for these populations, the revisions aim to ensure that clinicians can apply the criteria with greater precision across age ranges and clinical contexts.
Supporting this major publication, companion papers were also released, including the “2024 MAGNIMS-CMSC-NAIMS consensus recommendations on the use of MRI for the diagnosis of multiple sclerosis,” and “Recommendations on the use of optical coherence tomography and visual evoked potentials for fulfilling dissemination in space as part of the 2024 Revised McDonald Diagnostic Criteria for multiple sclerosis.”3,4 Additionally, a related paper published in eBioMedicine, titled “Positive cerebrospinal fluid in the 2024 McDonald criteria for Multiple Sclerosis,” offers further insights into the role of cerebrospinal fluid analysis in early detection.5