Blood tests are often the first line of testing for evaluating MS symptoms. They can’t confirm a diagnosis of MS, but they can help rule out other conditions or point to a diagnosis.

Multiple sclerosis (MS) is a chronic disease of the central nervous system (CNS). The immune system inflames the myelin that encases the nerve fibers, the cells that make the myelin, and the nerve fibers themselves.

The symptoms of MS vary from person to person. Problems with vision, balance, coordination, and fatigue are among the most common symptoms.

Blood tests help to rule out or confirm other health conditions with symptoms similar to those of MS. Often, other tests, such as an MRI, a spinal tap, or evoked potential exams, are also part of the diagnostic process.

This article takes a closer look at how blood tests are used to help diagnose MS.

One of the primary reasons doctors begin with blood tests when diagnosing MS is to find the cause of presenting symptoms.

Early symptoms of MS — such as vision problems, muscle weakness, or numbers and tingling — can be vague and potentially point to a number of different conditions, including:

A complete blood count (CBC) can point to anemia (low red blood cell count), vasculitis (high white blood cell count), and infection (a specific pattern of high white blood cells). This would be the first goal of blood test screening for someone with symptoms of MS.

Additionally, testing for thyroid hormone levels may also be part of the diagnostic process for MS symptoms.

Conditions that may cause symptoms similar to MS

Health conditions with similar symptoms to MS include:

  • Lyme disease: Lyme disease can cause tingling or numbness in your arms, hands, legs, and feet. These are also common symptoms of MS. While not 100% accurate, enzyme-linked immunosorbent assay and Western blot blood tests can detect the presence of Lyme disease infection in the blood.
  • Lupus: Systemic lupus erythematosus (SLE) is the most common type of lupus, according to the Centers for Disease Control and PreventionTrusted Source. It’s an inflammatory autoimmune disease that can affect your CNS and may cause numbness, tingling, fatigue, and vision problems. A blood test that is positive for antinuclear antibodies and other antibodies may indicate lupus or some other autoimmune disease but not MS.
  • Devic disease: Neuromyelitis optica, better known as Devic disease, is a rare immunological demyelinating CNS disorder that has some features similarTrusted Source to those of MS. However, it causes demyelination that affects the spinal cord and optic nerve, not the brain. The two conditions share many symptoms, such as blurred or lost vision, weakness, numbness, bladder problems, and spasticity. A test called the NMO-IgG blood test will be negative in people with MS but positive in 70% of people with Devic disease.

Vitamin deficiencies that may cause symptoms similar to MS

Certain vitamin deficiencies may also mimic the symptoms of MS. These include:

  • B12 deficiency: Demyelination, which is common in both B12 deficiency and MS, is damage to the protective covering that surrounds nerve fibers within the central nervous system. Symptoms of vitamin B12 deficiency include numbness and tingling in the hands and feet, weakness, and fatigue.
  • Copper-deficiency myelopathy: This is copper deficiency leading to spinal cord injury or damage. Doctors diagnose the condition based on a blood test that looksTrusted Source at the levels of copper and copper-carrying proteins in the blood. This condition can also mimic the symptoms of MS.

A vitamin D deficiency does not have similar symptoms to MS, but it may increase your risk of developing MS. In fact, people with MS often have a deficiency in vitamin D.

A person gets 80% to 90% of their vitamin D from exposure to the sun and the rest from food. The dietary sources of vitamin D are mainly:

  • fatty fish, such as salmon or sardines
  • beef live
  • cheese
  • foods fortified with vitamin D, such as milk

Blood testing can show whether a person has a vitamin D deficiency. Studies have shown that maintaining a healthy level of vitamin D may help reduce the risk of developing MS.

For people who already have MS, increasing vitamin D intake may help slow disease progression. However, the research on this is still not conclusive.Trusted Source

Generally, a series of tests are needed to rule out other potential conditions and meet the criteria for diagnosis of MS.

In addition to gathering symptom history and blood tests, your doctor might also order the following tests.

MRI imaging

An MRI is painless, noninvasive, and can produce detailed images of the brain and spinal cord.

Performed with and without contrast dye, an MRI can identify changes in the brain and spinal cord, such as stroke, bleeding, or demyelination. The images can show if demyelinating lesions are old, new, or currently active. In addition to diagnosis, an MRI can help monitor disease progression.

Spinal tap

Although lumbar puncture can’t rule out or confirm MS, it can help with diagnosis. Spinal fluid is obtained from a needle inserted between the bones of your lower spine.

In people with MS, the spinal fluid sometimes contains elevated levels of IgG antibodies or proteins called oligoclonal bands, which could also be caused by some other diseases. About 5% to 10% of people with MS have no spinal fluid abnormalities.

Evoked potential tests

A visual evoked potential test involves staring at a screen with an alternating checkerboard pattern.

This helps show how electrical activity in the brain responds to external stimulation such a sight or sound, and whether there’s any impairment of your optic nerve pathways.

There are different types of evoked potential tests. The visual evoked potential test is the most commonly used for assessing MS.

Eye exam

For many people, vision problems may be the first signs of MS. This can present commonly as optic neuritis, which is an inflammation of the optic nerve that can cause vision to become blurred, colors to become dimmed, pain in the eyes, blind spots, and contrast sensitivity.

Other MS-related problems include double vision and involuntary eye movements. Anyone who has these kinds of symptoms should visit their doctor. A doctor may provide a referral to an ophthalmologist, neurologist, or neuro-ophthalmologist if they suspect the cause could be MS.

Low-vision specialists

In addition, if you have optic neuritis and you continue to experience vision loss despite other treatments, you can also consult with a low-vision specialist. These are typically licensed doctors of ophthalmology or optometry. They can provide recommendations on support and strategies to help you live your best life with your level of vision.

The doctor will thoroughly examine your eyesight in terms of how it functions in your day-to-day life. This is a lengthy exam that lasts longer than a traditional eye exam.

They will also ask a lot of questions about your life. The visit may result in not only advice but also a prescription for an aid device, such as an optical device that fits your needs.

The symptoms of MS can be unpredictable, but doctors will typically look for the following:

  • dysesthesia, which is a more distinct MS symptom and feels like squeezing around the torso, kind of like the tightening of a blood pressure cuff
  • fatigue
  • difficulties with gait, such as limb weakness, balance problems, or sensory deficits
  • numbness on the face, arms, legs, or elsewhere on the body, which can show up as one of the earliest symptoms
  • spasticity, which is involuntary muscle spasms that most commonly happen in the legs
  • vision problems, such as blurred vision, poor contrast, problems with seeing colors, neuromyelitis optica, optic neuritis, or pain in the eyes, which can often show up as the first symptoms as well
  • vertigo or feeling lightheaded
  • problems with the bladder
  • sexual dysfunction
  • constipation
  • pain throughout the body
  • cognitive or emotional changes
  • depression
  • dysarthria (difficulty speaking or slurred speech)

Less common symptoms may also include:

  • problems with your hearing or taste
  • dysphagia (difficulty swallowing)
  • tremors
  • seizures
  • breathing problems

After you receive a diagnosis, you may feel a sense of shock or dread. You may have an idea about what MS looks or feels like from just one person who was affected. You may be experiencing symptoms that may or may not align with what you know about the disease.

There’s no cure for MS, so it can be helpful to allow yourself time to adjust to this new reality and to the fact that it requires a lifetime commitment to managing this disease.

In addition to your primary doctor, you’ll also need to add a neurologist to your healthcare team to help evaluate symptoms and monitor your disease progression.

Though sometimes MS can lead to severe disability, most people continue to have a good quality of life and can expect a typical life span with the support of their healthcare team.

You may find it helpful to join an MS support group, either online or in-person, as a complement to your treatment plan.

If you’re interested in sharing advice and stories in a supportive environment, consider joining the Healthline MS Buddy community. The MS Buddy app is free and available for iPhone or Android.

Although everyone’s experiences with MS are different, it might help to share your experiences with others.

The next step is to talk with your doctor and begin developing a treatment plan. It may be helpful to do some research on MS so you can come to your doctor’s appointment with some information and feel better prepared to ask questions about available treatments.

Visit this Multiple Sclerosis Resource hub for helpful articles and information about MS.

Here are some potential questions to ask.

Am I a candidate for disease-modifying drugs?

The Food and Drug Administration has approved one medication, ocrelizumab (Ocrevus), for treating primary-progressive MS (PPMS).

Other disease-modifying drugs exist on the market to reduce relapses and slow disease progression in relapsing MS, but they haven’t been shown to work for progressive types of MS such as PPMS. Clinical research is underway to develop other medications to treat these forms of MS.

In addition, these powerful drugs must be taken consistently to be effective, and they can have serious side effects. Be sure to discuss the pros and cons of each with your doctor. Other symptoms, such as fatigue, can also be treated.

What’s the best way to manage symptoms?

Ask your doctor what they recommend for symptom management. This may involve a number of strategies but will likely involve medications. The type of medication will depend on the type of symptoms you have.

The National Multiple Sclerosis Society lists a variety of sample medications commonly prescribed to manage a variety of common symptoms of MS.

What happens if my symptoms worsen?

The disease process of MS often tends to go into remission and then relapse. This is known as relapsing-remitting MS. If this happens and the relapse is severe, your doctor may put you on a treatment of corticosteroids. You may have to take this orally or receive it intravenously.

When this doesn’t work, additional treatment options may include plasmapheresis or Acthar Gel. Your doctor can advise you on the best course of action.