What is the diagnostic process for multiple sclerosis (MS)?

There is no specific test for multiple sclerosis (MS). Doctors will use several tests in order to rule out other conditions before a diagnosis is confirmed. A number of conditions mimic the symptoms of MS, some of which can be cured, while others require treatments different to those that are used for MS. With this in mind, it is vital that a doctor perform an extensive investigation and analysis before a diagnosis of multiple sclerosis is reached.

A doctor will usually begin by the patient’s complete medical history followed by a physical examination. After which he/she may recommend the following tests:

• Blood tests – These are conducted to aid in ruling out other conditions with similar symptoms to MS such as systemic lupus erythematosus(SLE), sarcoidosis, syphilis, Lyme disease, vitamin B12 deficiency, and HTLV-1 amongst others.
  
  Tests used to check for certain biomarkers (i.e. a gene, characteristic or molecule that defines a specific disease) that are associated with multiple sclerosis are still in development. The identification of these biomarkers may aid in diagnosing MS in the future.
• Spinal tap (lumbar puncture) – This test involves the doctor obtaining a sample of cerebrospinal fluid that is removed from the spinal canal and sent to a lab for analysis. The sample will then be screened for abnormalities such as inflammatory cells and proteins that are linked to MS and to rule out any other conditions that often have similarities to MS.
• MRI (magnetic resonance imaging) – This will be done of the spine and head (brain) in order for the lesions characteristic of MS to be identified. After the initial images of the spinal cord and brain are generated, a contrast agent or special dye will be injected into one of the patient’s veins, after which the MRI will be repeated.
  
  In the parts of the brain and spinal cord that have inflammation as a result of MS, there will be a disruption of the blood-brain barrier present and as a result, the dye may leak into MS lesions that are active. This indicates that the condition is in an active phase.
• Evoked potential tests – These forms of tests make use of electrodes placed on the skin to transmit electric signals (these are painless) in order for a doctor to measure the rate at which the patient’s nervous system responds to the stimulations. The doctor may also use visual stimuli where the patient will be required to watch a visual pattern that moves and the electrodes will measure the rate at which the information perceived by the eyes travels down the neural pathways.

The majority of patients suffering from RRMS (relapsing-remitting multiple sclerosis) will have quite a straightforward diagnosis based on their symptoms and the pattern in which they experience these being consistent with the classic symptoms of MS. This diagnosis will be confirmed by imaging scans conducted of the brain such as an MRI.

The diagnostic process of MS can be more complicated in people who suffer from unusual symptoms or diseases that are progressive. In cases such as these, additional testing will need to be conducted that involves cerebrospinal fluid analysis, evoked potential tests and other imaging tests in order to obtain a definite diagnosis.