What are Lyme disease tests?

Lyme disease is an infection caused by bacteria you get from tick bites. Lyme disease tests look for signs of infection in a sample of your blood or cerebrospinal fluid (CSF). CSF is a clear liquid that flows in and around your brain and spinal cord. The test checks your sample for antibodies that your immune system makes to fight the bacteria that cause Lyme disease.

You can get Lyme disease if an infected tick bites you. Ticks can bite you anywhere on your body, but they usually bite in hard-to-see places such as your groin, scalp, backs of the knees, and armpits.

Most Lyme disease is caused by bites from tiny, baby ticks that are no bigger than a pinhead. So you may not know you have been bitten. In general, an infected tick needs to be attached to you for 36 to 48 hours before it can give you Lyme disease bacteria.

Without treatment, Lyme disease can cause serious health problems that may affect your joints, heart, and nervous system. But if you find Lyme disease early, it can usually be cured after a few weeks of treatment with antibiotic medicine. If it's found later, treatment may take up to eight weeks.

Other names: Lyme antibodies detection, Borrelia burgdorferi antibodies test, Borrelia DNA Detection, IgM/IgG by Western Blot, Lyme disease test (CSF), Borrelia antibodies, IgM/IgG

What are they used for?

Lyme disease tests are used to find out if you have a Lyme disease infection. Your health provider is most likely to order the test if you have symptoms that could be Lyme disease, and you have or could have been exposed to infected ticks.

In the United States, infected ticks are most commonly found in states in the:

• Northeast
• Mid-Atlantic
• Upper Midwest
• Pacific coast, especially northern California

Why do I need a Lyme disease test?

You may need a test if you have symptoms of infection and were exposed or possibly exposed to ticks that carry the bacteria that causes Lyme disease. The first symptoms of Lyme disease usually show up between 3 and 30 days after the tick bite.

Early signs and symptoms may include:

• A reddish round skin rash that slowly gets bigger over several days. It usually doesn't itch or hurt, but it may be warm. As it gets better, it may look like a bull's-eye (a red ring with a clear center), but not always.
• Fever
• Chills
• Headache
• Fatigue
• Muscle and joint aches
• Swollen lymph nodes ("swollen glands")

Later signs and symptoms of Lyme disease usually affect your joints and nervous system. They include:

• Severe headaches and neck stiffness
• Rashes on other parts of your body
• Facial palsy (drooping of one or both sides of your face)
• Arthritis with severe joint pain and swelling, especially in the knees
• Pain that comes and goes in your muscles, joints, bones, and tendons
• Arrhythmia (a problem with the rate or rhythm of your heartbeat)
• Periods of feeling dizzy or short of breath
• Shooting pains, numbness, or tingling in your hands or feet

What happens during Lyme disease testing?

Lyme disease testing is usually done on a sample of blood. In certain cases, a cerebrospinal fluid (CSF) test may be done.

For a Lyme disease blood test:

A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

For a CSF test:

You may need a cerebrospinal fluid (CSF) test if your symptoms could mean that Lyme disease is affecting your nervous system, such as a stiff neck or numb hands or feet. Providers may order a CSF test if the results of your blood test show you likely have Lyme disease or if the results are uncertain.

To get a sample of your cerebrospinal fluid, a provider will do a procedure called a lumbar puncture, also known as a spinal tap. During the procedure:

• You will lie on your side or sit on an exam table.
• A provider will clean your back and inject an anesthetic into your skin, so you won't feel pain during the procedure. Your provider may put a numbing cream on your back before this injection.
• When the area on your back is completely numb, your provider will insert a thin, hollow needle between two vertebrae in your lower spine. Vertebrae are the small backbones that make up your spine.
• Your provider will withdraw a small amount of cerebrospinal fluid for testing. This will take about five minutes.
• You'll need to stay very still while the fluid is being withdrawn.
• Your provider may ask you to lie on your back for an hour or two after the procedure. This may prevent you from getting a headache afterward.

Will I need to do anything to prepare for the test?

You don't need any special preparations for a Lyme disease blood test.

For a lumbar puncture, you may be asked to empty your bladder (pee) and bowels (poop) before the test.

Are there any risks to Lyme disease tests?

There is very little risk to having a blood test or a lumbar puncture.

With a blood test, you may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

With a CSF test, you may feel a little pinch or pressure when the needle is inserted. After the test, you may feel some pain or tenderness in your back where the needle was inserted.

You may also have some bleeding at the site or get a headache. The headache may last for several hours or up to a week or more, but your provider may suggest treatment to help relieve the pain.

What do the results mean?

Lyme disease is difficult to diagnose. The symptoms are common to many conditions, and test results alone can't diagnose the disease. To make a diagnosis, your provider will consider your test results along with your medical history, exposure, and symptoms. You may also need other tests.

A negative blood test result means that antibodies to fight the Lyme disease bacteria were not found in your blood. If you had symptoms for longer than 30 days before your test, you probably don't have Lyme disease.

But if you had symptoms for less than 30 days before you gave your blood sample, you may need to have another Lyme disease test. That's because it may take a few weeks for your body to make enough antibodies to show up on a test. If your test was done too soon, you could be infected even though your test was negative. This is called a "false negative."

A positive blood test result means that antibodies to fight the Lyme disease bacteria were found in your blood. In this case, the Centers for Disease Control and Prevention (CDC) recommends a second blood test on the same blood sample. If the second test is positive and you have symptoms of infection, you probably have Lyme disease.

But positive test results don't always mean that Lyme disease is causing your symptoms. You could have antibodies from a past case of Lyme disease that your body successfully fought off months or even years ago.

It's also possible to have a "false positive." That means you don't have antibodies that fight Lyme disease bacteria, even though the test says you do. The test may have mistakenly found antibodies that fight other bacteria or diseases, such as certain autoimmune diseases. And it's possible that these diseases are causing your symptoms, not Lyme disease.

The results from a cerebrospinal fluid (CSF) test can help show whether Lyme disease has spread to your nervous system.

• A negative CSF test result means that no Lyme disease antibodies were found in your cerebrospinal fluid. But it doesn't rule out Lyme disease in your nervous system. You may need more tests.
• A positive CSF test result means that Lyme disease antibodies were found in your cerebrospinal fluid. If more antibodies were in your cerebrospinal fluid than in your blood, it's possible that Lyme Disease has spread to your nervous system.

Your provider will prescribe antibiotic medicine if you are likely to have Lyme disease. Most people who are treated with antibiotics in the early stage of disease will recover completely.

Learn more about laboratory tests, reference ranges, and understanding results.

Is there anything else I need to know about Lyme disease tests?

At-home test kits for Lyme disease are available. To do these tests, you usually collect a drop of blood from your finger and send it to a lab for testing. If you want to do an at-home test, it's important to talk with your provider first. Some at-home tests may use lab methods that aren't proven to work, so your results may not be accurate.