Does this test have other names?

Borrelia burgdorferi antibodies test, IgM/IgG test, Lyme disease test

What is this test?

This test measures the level of Borrelia antibodies in your blood. Borrelia burgdorferi bacteria cause Lyme disease.

The bacteria are spread to humans through the bite of an infected tick.

Lyme disease is the most common tick-borne illness in the U.S. If not treated, Lyme disease can cause an infection of the tissues covering the brain and spinal cord (meningitis). It can also cause: 

• Liver and heart problems

• Inability to control facial muscles (facial palsy)

• Problems that may show up months or years later, such as ongoing pain and tiredness, arthritis, and problems with memory and concentration

The CDC advises a 2-step evaluation of your blood test. First, your blood sample is tested through a process called enzyme immunoassay (EIA) or indirect immunofluorescence assay (IFA). If this is positive for Borrelia antibodies, the sample is put through an immunoblot test This is also known as a Western blot test. This test measures immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies in your blood. The CDC also recommends that an approved EIA test may be used in place of the immunoblot test as the second test.

You will likely receive a diagnosis for Lyme disease if both the EIA/IFA and the second test are positive. But in some cases, you may also have other tests, such on your cerebrospinal fluid (CSF).

Why do I need this test?

You may need this test if your healthcare provider thinks that you have Lyme disease based on recent travel, physical exam, and symptoms. Symptoms include a red bump that looks like a spider bite that spreads into a red rash in a classic "bull's-eye" pattern. You may also have:

• Fever

• Chills

• Headache

• Fatigue

• Swollen lymph nodes

• Muscle and joint aches

• Stiff neck

• Shooting pains in the hands and feet

What other tests might I have along with this test?

You may also have a test to look for Borrelia antibodies in your cerebrospinal fluid (CSF) if you have signs that your central nervous system has been affected. CSF is the liquid that surrounds the brain and spinal cord. This test may also be done if the blood test results aren't clear.

What do my test results mean?

Test results may vary depending on your age, gender, health history, and other things. Your test results may be different depending on the lab used. They may not mean you have a problem. Ask your healthcare provider what your test results mean for you.

A negative result means that no antibodies were found. But Lyme disease is hard to diagnose. This is partly because the antibodies may not show up in your blood for several weeks. If your results are negative shortly after you've been infected, the result could be a false-negative.

A positive result means that Borrelia antibodies were found and that you may have had or have Lyme disease. False-positive results sometimes do occur. This means the test could say you have the infection when you don't. For example, even if you have had Lyme disease and been cured, antibodies may still be found months or years later.

False-positive results can also happen if you have the autoimmune disease lupus, HIV, or syphilis. They can also happen if you have Helicobacter pylori bacteria or the Epstein-Barr virus.

How is this test done?

The test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand.

Does this test pose any risks?

Having a blood test with a needle carries some risks. These include bleeding, infection, bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may feel a slight sting or pain. Afterward, the site may be sore.

What might affect my test results?

The Lyme disease vaccine might affect your test results. If you are tested too soon after having been infected, you may get a false-negative result. If you have been treated with antibiotics, your results may also be affected.

How do I get ready for this test?

You don't need to prepare for this test. But be sure your healthcare provider knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illegal drugs you may use.