The MS Trust Podcast

Episode: How MS is diagnosed: your questions answered
Date: February 23, 2026
Hosts: Helena and Grace
Guest Expert: Professor Alastair Coles, Neurologist and MS Specialist

Overview

This milestone 100th episode focuses on one of the most pressing and confusing questions for those impacted by multiple sclerosis (MS): How is MS diagnosed? Hosts Helena and Grace, joined by renowned MS specialist Professor Alastair Coles, break down the evolving diagnosis process — from first symptoms, through key tests, to what happens when the results aren’t clear. The episode sheds light on the realities, challenges, and recent advances in MS diagnosis, addressing listener questions and demystifying the McDonald criteria.

Key Discussion Points & Insights

1. The Experience of Getting Diagnosed With MS

• The diagnostic process is highly individual. Some receive quick answers; for others, it takes years, with misdiagnoses and frustration along the way ([01:15]).
  • Stories shared: Symptoms dismissed as stress or migraines, long waits for referrals, or surprising diagnoses after unrelated MRIs ([01:40]).
• Desire for clarity: Most seek understanding about what’s happening and why tests are needed ([03:00]).

“They just wanted someone to explain what was happening to them, what the tests were for and why a diagnosis can sometimes take time.”
— Grace ([03:00])

2. How MS Diagnosis Has Changed

• Historical approach: Previously, diagnosis was less precise, especially before effective treatments existed.
  • “We were really quite casual about the diagnosis of MS, and we diagnosed a lot of things that, when I look back, probably weren’t MS… Then along came MRI scanning. That was the biggest change.”
    — Prof. Coles ([04:26])
• Rise of MRI: MRI has revolutionized diagnosis, becoming central where available ([05:29]).

3. First Signs and Referral Challenges

• Symptoms vary widely: Issues can include bladder problems, vision changes (optic neuritis), numbness, dizziness, and more. Many symptoms are common with other conditions ([05:38]).
• GP awareness is limited: On average, a GP may only be directly involved in 3-4 MS diagnoses in their lifetime, leading to delays ([07:17]).
• Socioeconomic inequalities: Diagnosis is often faster for those who are articulate, middle-class, and in well-served regions ([07:57]).

“If you’re middle class and articulate and living in Cambridge, it should be a matter of weeks. But if you’re living in a coastal town and you’re in a poor socioeconomic area, we know that it takes many more months.”
— Prof. Coles ([07:57])

• Advice for self-advocacy: Persist in requesting referrals, especially if concern is sustained or family history exists ([11:21], [55:05]).

4. The Complexity of Symptoms

• Transient and broad: Early MS symptoms often disappear, making recognition and diagnosis difficult for patients and GPs ([09:40]).
• Fatigue as a common, but non-specific sign: “Fatigue is a very prominent symptom, early on in MS, but of course… not unexpected in the ordinary population.” — Prof. Coles ([10:49])

5. The McDonald Criteria and Diagnostic Tests

a. What are the McDonald Criteria?

• Evolving diagnostic benchmarks designed to make MS diagnosis both accurate and early, especially for research purposes ([14:03]-[16:00]).
• Primarily based on:
  • Clinical attacks and examination
  • MRI evidence
  • Spinal fluid (lumbar puncture) findings
• The latest (2024) criteria allow for diagnosis even before symptoms, if imaging and other signs strongly fit MS ([19:53]).

“What we’ve ended up with in this latest version is that it’s even possible to diagnose MS in someone who has had no symptom…our treatments are so effective, we want to get at people before they’ve even had symptoms.”
— Prof. Coles ([17:53])

b. Tests Typically Used

1. MRI Brain/Spinal Cord

   • Now “mandatory” in the UK ([23:16]).
   • Shows number, location, and sometimes the shape of lesions. The latest criteria recognize the optic nerve and include special markers like the central vein sign and paramagnetic rim lesions ([29:35], [30:15]).
   • Not all MRI scanners or radiologists are equipped to detect next-generation markers ([31:38]-[32:27]).

2. Blood Tests

   • Not specific for MS, but critical for excluding other conditions (e.g., lupus, B12 deficiency, HIV). Essential to rule out so-called ‘mimics’ ([44:55]).

3. Lumbar Puncture (Spinal Tap)

   • Checks for oligoclonal bands or kappa light chains (markers of central nervous system immune activity) ([35:00]).
   • Becoming more common again, especially for diagnosing progressive MS or when imaging isn’t conclusive ([40:26]-[41:21]).
   • Newer lab techniques have made this test more widely accessible and less reliant on highly trained staff ([36:43]).

   “We’re doing them more and more...especially in people with progressive MS, where you have one site affected, usually the spinal cord.”
   — Prof. Coles ([34:16])

   • What’s it like?: Usually quick and safe, done with anesthetic and a thin needle; rare complications like headaches can occur, most resolve in days. Not done at the first appointment ([37:22]).

4. Visual Evoked Potentials (VEPs) and Optical Coherence Tomography (OCT)

   • Both assess optic nerve involvement, which is newly emphasized in criteria ([24:46], [45:45]).
   • VEPs: Measures brain response to visual stimuli; returning to practice for early diagnosis ([42:11]).
   • OCT: Painless, optician-based scan to assess retinal nerve fibers for past optic neuritis ([45:53]).
   • OCT may become more common due to convenience and accessibility ([47:50]).

6. When Diagnosis Remains Unclear

• Limbo state: Sometimes test results and clinical picture remain inconclusive.
  • Follow-up scans in 6–12 months are common to monitor for changes ([48:29]-[49:44]).
  • Important not to rush diagnosis due to significant implications of labeling someone with MS ([50:01]).

“We want to be really sure when we say someone has MS, that is the case.”
— Prof. Coles ([50:01])

7. After the Diagnosis: Next Steps & Treatment

• For those diagnosed:

  • Access support (information, personalized advice from MS nurses) ([51:02]).
  • Begin conversations about treatment options. Early, but not rushed — timeframes are months, not weeks ([52:48]).
  • Critical window: Most effective treatments are best begun within five years of first symptom ([52:48]-[53:47]).

  “I think it’s good to get started on any treatment within a matter of months, not weeks or days...the key time point for me is five years after the first symptom.”
  — Prof. Coles ([52:48])

• Treatment never starts without a clear diagnosis ([53:54]).

• For those not diagnosed:

  • May be referred for further tests, or simply discharged with reassurance ([50:22]-[50:58]).

8. Preparation and Self-Advocacy Tips

• Come prepared: Limited appointment time means it’s crucial to come with a symptom diary and clear questions ([13:19], [60:50]).
• Polite persistence: If you have persistent concerns, request a referral to a neurologist ([55:05]).
• No one should feel alone during the process: MS Trust offers a helpline and information resources regardless of diagnosis status ([62:20]).

Notable Quotes & Memorable Moments

• On inequalities in MS diagnosis:

  “We know that it takes many more months… That’s just one of the many examples of inequalities in the way that people with MS are treated.”
  — Prof. Coles ([07:57])

• On the evolving criteria:

  “It’s even possible to diagnose MS in someone who has had no symptom… think of it a bit like breast cancer or prostate cancer. Wouldn’t we want to be able to diagnose those things really early, even before they caused any symptoms?”
  — Prof. Coles ([17:53])

• On the role of new MRI markers:

  “If you see a vein in the middle of a patch of inflammation…that’s very likely to be MS…it’s a pretty slam dunk.”
  — Prof. Coles ([30:15])

• On preparation for appointments:

  “It’s in your best interests to be really well prepared…be clear about what you feel has happened…helpful to write it down and make notes for yourself and of questions.”
  — Prof. Coles ([13:19])

• On the support needed post-diagnosis:

  “Someone who’s just been diagnosed…needs to be offered…information from trusted organisations, but also personalised, ideally from an MS nurse or someone who understands MS well.”
  — Prof. Coles ([51:02])

Important Timestamps

• [04:26] — Prof. Coles describes how diagnosis has evolved, the arrival of MRI.
• [05:38] — Early symptoms leading to MS diagnosis.
• [07:57] — Discussion of diagnostic delays and inequalities.
• [14:03] — What are the McDonald criteria? Why do they matter?
• [17:53] — Diagnosis possible before symptoms using new criteria.
• [23:16] — The essential diagnostic tests, especially MRI.
• [34:16] — Why lumbar punctures are back in use and particularly important in progressive MS.
• [45:53] — OCTs as a tool in diagnosis.
• [48:29] — What happens when diagnosis is inconclusive.
• [52:48] — Timeframes for starting MS treatment.
• [55:05] — Guidance for those worried about MS symptoms.

Listener Guidance & Final Takeaways

• Diagnosis is complicated — Symptoms are inconsistent and overlap with many other conditions.
• Persistence is essential — If worried, especially with family history or persistent symptoms, escalate your concerns politely to your GP.
• Come prepared to appointments — Record symptoms, bring questions, and express your concerns clearly.
• Diagnosis leads to support and information — Early support, trusted advice, and consideration of therapy form the next steps.
• MS Trust is here to help at any stage — Resources are available whether you’re waiting, unsure, newly diagnosed, or just supporting someone else.

Links and Further Resources

• MS Trust Helpline: 0800-323-839
• How MS Is Diagnosed: mstrust.org.uk/how-is-ms-diagnosed
• Videos on tests and procedures: (Link in episode show notes)

“You don’t have to wait for a diagnosis to get support.”
— Grace ([62:20])