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The updated McDonald Diagnostic Criteria for MS have now been published, offering clinicians new tools to support earlier diagnosis, reduce uncertainty, and improve outcomes for Australians affected by the disease. Adoption into clinical practice is expected to follow as awareness and access to diagnostic tools grow.
Multiple sclerosis (MS) affects over 33,000 Australians, with prevalence rising at an accelerated rate. It is the most common neurological cause of disability in young adults, typically diagnosed between the ages of 20 and 40. Notably, MS affects women around three times more often than men.
The disease presents with a wide range of symptoms that vary from person to person. These may include fatigue, vision problems, numbness or tingling, muscle weakness, and difficulties with coordination or balance. Because symptoms can be intermittent or subtle in the early stages, diagnosis is not always straightforward.
MS Australia’s World MS Day ‘My Diagnosis’ report highlights the significant emotional and physical toll that delays in diagnosis can have. Drawing on data from the Australian MS Longitudinal Study, the report found that the average time from symptom onset to diagnosis is nearly four years.
In MS, time is brain. The importance of timely diagnosis in MS is well recognised. Delays can increase the risk of neurological damage and missed opportunities for early treatment. Early diagnosis not only enables access to disease-modifying therapies but also provides clarity and reassurance to patients and their families.
The updated McDonald Diagnostic Criteria for MS, recently published by an international panel of experts in The Lancet Neurology, aims to address these challenges head-on, offering clinicians new tools to diagnose MS faster and more accurately.
What’s new in MS diagnosis?
The McDonald Diagnostic Criteria for MS have been the gold standard for MS diagnosis since 2001, evolving with advances in research and technology. Named after New Zealand neurologist Professor Ian McDonald, the criteria have undergone four major updates, with the 2024 revision reflecting the latest evidence and expert consensus. The changes are designed to help clinicians confirm MS earlier, even when symptoms are mild or atypical.
Key updates include:
- Earlier diagnosis through MRI: Radiologically Isolated Syndrome (RIS) — MS-like changes seen on MRI, even without symptoms — can now be diagnosed as MS if supported by other tests.
- Streamlined process: Clinicians no longer need to demonstrate “dissemination in time” (damage occurring at different dates). A single episode of symptoms may suffice if other signs are present.
- Expanded diagnostic tools: The optic nerve is now a key area for assessment. Optical Coherence Tomography (OCT), a simple eye scan, can detect optic nerve damage. New spinal fluid tests (kappa free light chains, or kFLCs) can confirm MS without the need for older oligoclonal band tests, speeding up diagnosis for some patients.
- Unified framework: The criteria now cover all MS types, including primary progressive MS, making diagnosis more consistent.
- Improved accuracy: MRI remains central, but new signs, such as the central vein sign (CVS) and paramagnetic rim lesions (PRLs), help distinguish MS from other conditions. For older adults and children, additional tests are recommended to reduce misdiagnosis.
These updates are grounded in robust international research and have been peer-reviewed and published in The Lancet Neurology. They offer clinicians greater flexibility and confidence, reducing delays and uncertainty for patients. Importantly, these changes may also help general practitioners recognise and refer suspected cases of MS earlier, streamlining the pathway to specialist assessment.
The updated criteria are more than a technical revision — they represent a global commitment to improving MS care. For Australian clinicians, this means earlier intervention, better patient outcomes, and reduced diagnostic uncertainty. For patients, it means clarity, relief, and timely access to treatment.
From guidelines to patient care: making the most of the new criteria
Clinicians can begin applying the new McDonald Diagnostic Criteria for MS immediately, with educational resources currently being developed to support a smooth transition. To ensure all Australians benefit from these advances, it’s important that health services and government prioritise wider access to advanced diagnostic tools such as Optical Coherence Tomography (OCT) and kappa free light chain (kFLC) testing. Investment in training and equipment will be key to making these technologies broadly available.
Importantly, these changes pave the way for more personalised care from the outset, allowing clinicians to tailor treatment plans to each individual’s needs and ultimately improving long-term health and quality of life for people living with MS.
As Australia’s national not-for-profit organisation dedicated to solving MS, MS Australia welcomes these updates as a significant step forward in the diagnostic pathway. In line with our mission to empower research, advocate for systemic change, and support the MS community, we see these changes as an opportunity to improve diagnostic accuracy and reduce delays. They equip clinicians to act sooner and with greater confidence, and give patients the clarity and support they deserve. The next step is ensuring equitable access to diagnostic tools and consistent education for healthcare professionals, so that all Australians affected by MS can benefit from these advances.
Dr Tennille Luker is Head of Research at MS Australia.
Dr Julia Morahan is Deputy Chief Executive Officer of MS Australia.
Rohan Greenland is Chief Executive Officer of MS Australia and Chair of Neurological Alliance Australia (NAA).
Professor Todd Hardy is a Senior Staff Specialist Neurologist and Chair of the Australia and New Zealand Association of Neurology MS and Neuroimmunology Group.
The statements or opinions expressed in this article reflect the views of the authors and do not necessarily represent the official policy of the AMA, the MJA or InSight+ unless so stated.
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