Implementing the 2024 MS diagnostic criteria: what earlier detection means for UK services

Implementing the 2024 MS diagnostic criteria: what earlier detection means for UK services

The 2024 McDonald criteria mark a pivotal moment in MS, by shifting the diagnostic framework from clinical presentation to imaging and biological evidence. The aim is to enable earlier, more confident diagnosis, even for some asymptomatic patients.

Speaking at a recent MS Academy webinar, Dr Kate Petberam, consultant neurologist at South Tyneside & Sunderland NHS Foundation Trust, explained the criteria include five "key shifts".

The optic nerve is now recognised as a fifth anatomical location for demonstrating dissemination in space (DIS). The central vein sign (CVS) has been incorporated as an MRI biomarker to improve diagnostic specificity, while paramagnetic rim lesions (PRLs) are now recognised as supportive imaging biomarkers, and kappa free light chains (kELÇ) in cerebrospinal fluid are now accepted as an alternative to oligoclonal bands as evidence of intrathecal inflammation, providing another supportive biomarker for diagnosis.

The revised criteria also set out unified pathways across disease phenotypes and adult/paediatrics, and allow for the earlier diagnosis in selected individuals with radiologically isolated syndrome (RIS).

The challenge for healthcare teams is implementing these changes into clinical practice. "We are going to have to talk to our MRI departments and develop business cases for kELS, and talk to our ophthalmology colleagues about consistent optic nerve assessments," said Kate. "We want to reduce unwarranted variation, so will need to work towards consistent access to these pathways across regions, and we are going to have to communicate this to patients and update our accessible patient information, particularly regarding earlier diagnosis."

Making the new criteria work in practice

Multidisciplinary collaboration will be central to implementing these changes effectively, said Professor Tarunxa Arun, consultant neurologist at University Hospitals Coventry and Warwickshire NHS Trust.

Advances in MRI technology, and cerebrospinal fluid biomarkers such as KELS, as well as the incorporation of novel imaging markers such as the CVS and PRLs, have expanded diagnostic capabilities. However, successful implementation depends on coordinated working between neurologists, neuroradiologists, specialist nurses, ophthalmologists and laboratory services to ensure diagnostic findings are interpreted accurately and consistently.

"We are entering a really fantastic era in MS management and I feel fortunate to be practicing in this time," said Tarunya. "But it also means we have a responsibility we cannot shy away from. We need to think about the impact these things will have on our practice, so we can make a diagnosis early." Additional signs and markers, she went on, meant "we have to talk to each other more". "We need to develop greater multidisciplinary team (MDT) collaboration, and when things become complicated, we need to phone a friend."

As the revised criteria place greater emphasis on advanced MRI interpretation and additional paraclinical investigations, specialist expertise and standardised reporting are needed. Yet, while these developments improve diagnostic sensitivity and reduce the need for invasive procedures or prolonged diagnostic surveillance, they also create challenges for centres with limited access to specialist imaging techniques or experienced radiologists. As such, collaboration between regional networks and specialist centres is essential to ensure equitable implementation and reduce variation in practice, she added.

Tarynxa also emphasised the need for robust diagnostic safeguards to minimise the risk of misdiagnosis. This is particularly true in older people and those with comorbidities in which alternative neurological conditions may mimic MS. Effective communication between clinicians is paramount, she explained, encouraging the discussion of complex cases and the shared interpretation of imaging and clinical findings. Equally important is collaboration with patients, through shared decision-making, particularly when considering early treatment in RIS, she went on.

"Treatment decisions should remain individualised," she said.

Ultimately, as diagnostic pathways become ever more sophisticated, healthcare teams will need to look beyond the technological advances, and think about how to ensure timely, equitable diagnosis and appropriate treatment for all. The key, Jacova believes, is fostering collaborative practice, standardising expertise, and individualising treatment decisions.

Preparing services for earlier diagnosis

Ruth Stross, director of services and health professional lead at MS Trust, said the criteria represent

"an exciting opportunity" to improve earlier diagnosis and access to treatment, potentially improving long-term outcomes. Implementing them into clinical practice, however, "is complicated" and can raise new communication challenges, she added.

Ensuring patients receive clear, consistent information about these increasingly complex diagnostic pathways is paramount. The MS Tcust has already received enquiries from people confused by changes to the criteria, with some asking whether they should be reassessed after previously being told they did not have MS. Many patients, Ruth went on, felt overwhelmed by uncertainty surrounding diagnosis and treatment decisions, adding that this was set against a backdrop of already overstretched services. "It can feel like diagnosis is happening faster than our services are able to adapt," she said.

Earlier diagnosis, she went on, shifts the workload to earlier in the disease course; it does not reduce it. Services are seeing an increased volume of patients, and more time is needed to explain the diagnosis, to support treatment decisions, and to provide holistic follow-up - this is despite a preexisting gap in workforce capacity.

Furthermore, there are currently variations in how the criteria are being utilised in clinical practice across the country. Early adopter centres are using the updated criteria and diagnosing sooner, and as such are seeing an increased demand. Late or partial adopters are still working within older frameworks, resulting in delayed diagnosis and treatment initiation. For patients, this is leading to a "postcode effect" in access.

"This is tricky to navigate and we do not have all the answers," said Ruth, acknowledging that adoption was heavily reliant on funding and workload. However, there are some tools and frameworks which can be useful when redesigning services, building business cases, and talking to commissioners.

These include Annex A of NHS England's Specialised Neurology Services specification, which becomes a contractual requirement for providers commissioned to deliver specialised neurology services from April 2026. It sets out the minimum clinical service standards for MS, and includes local access to neurologists who can diagnose and explain MS, to MRI, and to specialist nurses who can discuss and approve DMTs.

"We do need to be looking at service redesign," said Ruth. "The criteria gives us the opportunity to try to work together and avoid overwhelm."

Supporting patients through earlier diagnosis

Earlier diagnosis offers several potential benefits to patients, said Christine Lenginotti, highly specialist clinical psychologist at Chelsea & Westminster NHS Foundation Trust. It enables, for example, earlier access to DMTs, which many patients view as a way of gaining control over their condition, and it may also shorten the psychologically difficult period of diagnostic uncertainty.

However, diagnosing people before they have developed significant symptoms can also present challenges, and people may find it more difficult to adjust to the news. Diagnosis, she explained, often requires people to redefine themselves, moving from identifying as a healthy person to integrating MS into their concept of themselves. Earlier diagnosis may complicate this process, because people have little lived experience to connect with the diagnosis. "If people are diagnosed when there are no symptoms present, how do they make sense of MS and what that looks like for them?", asked Christine.

She also discussed the idea of ambiguous loss, describing it as "a loss that's unclear, unresolved, or lacks closure." Patients may feel healthy while simultaneously living with the knowledge of a lifelong condition, and this can create cognitive dissonance and uncertainty, leading to heightened symptom monitoring. Evidence from Huntington's disease suggests this can lead to social withdrawal, reduced future planning and increased anxiety.

Patient-centred communication, shared decision-making and informed choice are critical to supporting people through an early diagnosis, Christine believes. That means exploring patients' concerns with "curiosity and with kindness", acknowledging their emotions, providing clear information, and tailoring discussions to their individual coping style.

Structured communication approaches such as the SPIKES model can help with this process. This six-step framework for delivering difficult news is designed to help clinicians communicate diagnoses compassionately, by ensuring an appropriate setting, understanding the patient's perspective, providing clear information, responding empathetically, and agreeing on a plan for next steps.

Ultimately, Christine concluded, earlier diagnosis has clear clinical advantages. But services must also recognise and address the accompanying psychological, social and identity-related challenges.