If you suspect that you have multiple sclerosis (MS) or another neurological condition, make an appointment with your doctor right away. Even early-stage MS can result in lasting neurological damage. Confirming or ruling out MS can help you start treatment as soon as possible.

No single set of symptoms, physical changes, or tests is enough to definitively diagnose MS. Your doctor may need to conduct multiple tests to rule out other possible causes of your symptoms. Read more to learn what you can expect from the diagnostic process.

To diagnose you with MS, your doctor must find:

  • evidence of damage to two separate areas of your central nervous system (CNS), such as your brain, spinal cord, and optic nerve
  • evidence that damage to your CNS has occurred on separate occasions, at least one month apart from each other
  • no evidence that the damage has been caused by other diseases

MS can cause a variety of symptoms. Some common symptoms include:

  • fatigue
  • dizziness
  • muscle weakness
  • muscle stiffness
  • balance problems
  • numbness or tingling
  • vision problems
  • bladder or bowel problems
  • sexual dysfunction
  • cognitive changes
  • emotional changes

Most people with MS are diagnosed between the ages of 20 and 50, reports the National Multiple Sclerosis Society (NMSS). But in some people, symptoms develop at a younger or older age.

According to the NMSS, symptoms begin before age 18 in approximately 2 to 5 percent of people with MS. In some cases, the condition may masquerade as other childhood diseases. This can make diagnosis more complicated. Young children may also have trouble verbalizing certain symptoms.

Late-onset MS occurs when the initial symptoms of MS develop after age 50. It may take more time for your doctor to diagnose the cause of your symptoms if you develop them later in life. Some symptoms of MS overlap with age-related conditions that can develop in older adults.

The first step in diagnosing MS is taking a thorough medical history. Your doctor will ask you about your symptoms, including when they began and whether you’ve noticed any patterns or triggers. They may also ask you about:

  • injuries, diseases, or other health conditions that you’ve been diagnosed with
  • medical tests or treatment that you’ve recently undergone, including surgeries
  • medications that you’re currently taking or have recently taken
  • conditions that run in your family

Your doctor may ask you about your diet, exercise routine, bathroom habits, and sexual health. They may also evaluate potential environmental factors, such as your exposure to toxins or travel to high-risk areas.

Your doctor may conduct or order a neurological exam to assess how your nervous system is working. They may:

  • ask you questions about the date, time, and place to evaluate your cognitive faculties
  • ask you to push against their hand, stand on one foot, or perform other movements to evaluate your motor function and balance
  • test your ability to feel temperature and sensation
  • test your reflexes

They may also evaluate how the 12 cranial nerves of your brain are working. These nerves affect your ability to see, chew, swallow, and smell, among other things.

Based on your medical history and neurologic exam, your doctor may give you a tentative diagnosis of MS. They may also order additional tests.

Your doctor may use magnetic resonance imaging (MRI) to examine your brain and spinal cord. They can use an MRI test to check for lesions, or scarring. This test allows them to distinguish between old and recently formed lesions.

MS can’t be diagnosed with MRI tests alone. According to the NMSS, MRIs don’t show brain lesions in about 5 percent of people with MS. Lesions on your brain can also signify other conditions, particularly if you’re an older adult.

If you have MS, damage to the myelin sheath on your optic nerve will slow the transmission of signals along the nerve. Your doctor can use a visual evoked potential (VEP) test detect these changes.

During a VEP test, your doctor will attach wires to your scalp to assess your brain activity. Then they will ask you to sit in front of a screen displaying alternating patterns. While you watch the screen, they will measure the transmission of visual stimulation along the path of your optic nerve.

A spinal tap is also known as a lumbar puncture. Your doctor can use it to collect a sample of your cerebrospinal fluid (CSF) for testing. Specifically, they will check your CSF for the presence of oligoclonal bands.

Oligoclonal bands are proteins that indicate an immune response in your CNS. According to the NMSS, most people with MS have oligoclonal bands in their CSF. But the presence of these bands alone isn’t enough to diagnose MS. They may also indicate another condition.

Your doctor may order blood tests to help confirm or rule out other conditions that might be responsible for your symptoms. For example, they may use blood tests to check for signs of:

  • lupus
  • Lyme disease
  • neuromyelitis optica (NO)
  • acute disseminated encephalomyelitis (ADEM)
  • certain genetic disorders with symptoms that overlap with those of MS

Arriving at a diagnosis of MS takes time and persistence. If you suspect you might have MS, it’s important to seek care right away. The sooner you’re diagnosed, the sooner you can begin receiving treatment.

If you’re diagnosed with MS, your doctor will prescribe disease-modifying medications. These medications can help reduce MS attacks, lower the number of new lesions you develop, slow the progression of the disease, and improve your quality of life. Your doctor may also recommend physical therapy, occupational therapy, or other treatments.