No single set of symptoms, physical changes, or tests is enough to definitively diagnose multiple sclerosis (MS). Your doctor or specialist may need to conduct multiple tests to rule out other possible causes for your symptoms.

But if you suspect you may have MS or another neurological condition, reach out to 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. Here’s what you can expect from the diagnostic process:

To diagnose MS, a 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
  • evidence of oligoclonal bands (OCB), a protein in your spinal fluid
  • no evidence that the damage has been caused by other diseases

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

According to the National Multiple Sclerosis Society, most people are diagnosed with MS between ages 20 and 50. But in some people, symptoms may develop at a younger or older age.

In some childhood cases of MS, 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 with which you’ve been diagnosed
  • medical tests or treatments 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 also 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 neurological 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 to check for lesions or scarring. This test allows them to distinguish between old and recently formed lesions.

MS can’t be diagnosed with an MRI alone. It’s also important to note that MRIs don’t always show brain or spinal lesions, depending on the quality of the MRI scanner.

Lesions on your brain can also signify other conditions, particularly in older adults.

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 to detect these changes.

During a VEP test, your doctor will attach wires to your scalp to assess your brain activity. Then, they’ll ask you to sit in front of a screen displaying alternating patterns.

While you watch the screen, they’ll measure the transmission of visual stimulation along the path of your optic nerve.

A spinal fluid analysis test is also known as a lumbar puncture. Your doctor can use it to collect a sample of your cerebrospinal fluid (CSF) for testing.

They will check your CSF for the presence of:

  • elevated levels of immunoglobulin G (IgG) antibodies
  • proteins known as oligoclonal bands
  • high amounts of white blood cells

Oligoclonal bands (OCB) are proteins that indicate an immune response in your CNS. While research varies, many people with MS have OCB 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.

These can include infections of the central nervous system, inflammatory diseases, genetic disorders, nutrient deficiencies, and structural damage to the spine or brain.

For example, they may use blood tests to check for signs of:

New tests are being developed every day to help make diagnosing MS easier, and to ease symptoms after diagnosis.

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, lifestyle changes, or other treatments.