Diagnosing MS

MS is complex and can have many different symptoms. Early MS may present itself as a history of vague symptoms, which may occur sporadically over a prolonged period of time and could often also be attributed to other medical conditions.  

Invisible or subjective symptoms are often difficult to communicate to doctors and health professionals, and diagnosis can often take several months, or even longer. 

Even when a person shows a ‘classic’ pattern of MS-type symptoms, the symptoms must conform to agreed criteria (called the McDonald criteria, most recently updated in 2024) before a doctor or neurologist can diagnose clinically ‘definite’ MS. 

There is no simple test for MS. To make a diagnosis, neurologists typically use a combination of tests to rule out other conditions and look for signs of MS. These tests include: 

Neurological Exam 

Neurological exams play a key role in diagnosing MS. These exams help neurologists evaluate how well your central nervous system is working. MS can damage the protective coating around nerves called myelin, slowing down signals and causing symptoms like muscle weakness or numbness. 

During the exam, a neurologist will check your reflexes, balance, coordination, and other functions to pinpoint where your symptoms might be coming from. While this test alone can’t confirm MS, it’s an important first step in the diagnostic process.

Click here to watch our animation explaining neurological exams.

Magnetic resonance imaging (MRI) 

Magnetic Resonance Imaging, or MRI is currently the most accurate, non-invasive imaging method to detect demyelination and diagnose MS. An MRI scan uses powerful magnets to create detailed pictures of the brain and spinal cord. This helps doctors spot areas of damage which could be signs of MS. MRI scans can help doctors see how much damage has occurred and where it has taken place. 

Click here to watch our animation explaining MRI tests.

Lumbar puncture or spinal tap 

A Lumbar Puncture (spinal tap) is a useful tool that can help doctors diagnose MS. During this test, a doctor takes a small sample of the fluid around your brain and spinal cord, called cerebrospinal fluid, or CSF. The sample is sent to a lab for signs of MS, such as antibodies in the fluid. These antibodies indicate that your immune system is active in your brain and spinal cord. 

Click here to watch our animation explaining lumbar puncture tests. 

Evoked potentials tests 

An Evoked Potentials Test help doctors understand how quickly messages travel along your nerves. These tests can be a useful tool for diagnosing multiple sclerosis particularly at the earlier stages of MS before symptoms appear. Your brain generates electrical currents when processing information from your senses. Evoked potential tests measure the time it takes for your brain to receive signals from the eyes, ears and skin. If MS has damaged myelin, the protective coating around your nerves, messages from your nerves may travel more slowly. 

Click here to watch our animation explaining evoked potentials tests.

Tests for other conditions 

People may be given tests to rule out other conditions that have similar symptoms to MS, such as blood tests to look for the presence of specific antibodies. 

Early and accurate MS diagnosis 

An early diagnosis is vital to enable early treatment with disease modifying therapies that can minimise relapses and reduce future disability. Diagnosis also allows for lifestyle changes to help manage MS and improve quality of life. However, 83% of countries worldwide experience issues that prevent an early diagnosis of MS. (Atlas of MS) 

MRI machine with operator. Photo: Robert van Willigenburg

A set of images from a Magnetic Resonance Imaging scan