The Lyme disease blood test looks for antibodies (IgG and IgM) in the blood to the bacteria Borrelia burgdorferi that causes Lyme disease. The test is used to help diagnose Lyme disease.
How the Test is Performed
A blood sample is needed.
A laboratory specialist looks for Lyme disease antibodies in the blood sample using the ELISA test. If the ELISA test is positive, it must be confirmed with another test called the Western blot test.
How to Prepare for the Test
You do not need special steps to prepare for this test.
How the Test will Feel
When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away.
Why the Test is Performed
The test is done to help confirm the diagnosis of Lyme disease.
A negative test result is normal. This means none or few antibodies to Lyme disease were seen in your blood sample. If the ELISA test is negative, usually no other testing is needed.
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your health care provider about the meaning of your specific test results.
What Abnormal Results Mean
A positive ELISA result is abnormal. This means antibodies were seen in your blood sample. But this does not confirm a diagnosis of Lyme disease. A positive ELISA result must be followed up with a Western blot test. Only a positive Western blot test can confirm the diagnosis of Lyme disease.
For many people, the ELISA test remains positive, even after they have been treated for Lyme disease and no longer have symptoms.
A positive ELISA test may also occur with certain diseases not related to Lyme disease, such as rheumatoid arthritis.
There is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight but may include:
- Fainting or feeling lightheaded
- Multiple punctures to locate veins.
- Hematoma (blood buildup under the skin)
- Excessive bleeding
- Infection (a slight risk any time the skin is broken)
Lyme disease serology; ELISA for Lyme disease; Western blot for Lyme disease
Source: MedlinePlus, National Library of Medicine
MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.