Lyme Disease Blood Test

A Lyme disease blood test does not always show the presence of the bacteria responsible for causing Lyme disease. Blood testing is an invasive procedure, and many doctors regard blood tests for Lyme disease as medically unnecessary. Most doctors prefer to make the diagnosis of Lyme disease based on the symptoms that the patient has, and on a physical exam of the patient, rather than ordering a lot of invasive and expensive blood tests.

BUT sometimes a patient will turn up who has clinical symptoms that are similar to Lyme disease, but they cannot recall if they were bitten by a tick or not. In those instances, it may be necessary for blood tests to determine the cause of the patient's symptoms, and to rule out Lyme disease.

The most commonly accepted Lyme disease blood test is called the ELISA test. ELISA stands for enzyme-linked immunosorbent assay.

This specific test actually looks for the antibodies that the human body makes in response to the causative bacteria Borrelia Burgdorferi. It does NOT test for the bacteria itself - it looks for the cells that the human body creates to try and fight the bacteria!

When the human body is challenged by a specific bacteria, it begins to produce antibodies to try and kill that foreign bacteria. This is how your immune system works. These antibodies that the immune system has created are specific for the bacteria that has triggered the immune response. They are unique, they only work against that one type of bacteria. These specific antibodies can be detected using the ELISA test. SO, if the ELISA teat shows that you have the antibodies against the Borrelia bacteria, the ONLY WAY you could have them is if you have the Borellia bacteria in your system.


During the early stages of the disease, the test may not show up as positive. It takes a little while for your immune system to generate the antibodies, even though the bacteria are growing in your system.

Lyme Disease Blood Test

However, if there are other clinical symptoms of Lyme disease, your doctor may well make the assumption that you DO have Lyme disease, and start to treat you, while he waits for a subsequent ELISA test to show positive.

For information on the symptoms of Lyme Disease, go to Symptoms Lyme Disease

In order to CONFIRM a positive result received from the ELISA testing, another different test is needed. This is called a Western blot test.

This particular test confirms that there are actual antibodies to the Borrelia Burgdorferi bacteria. After confirmation of diagnosis, treatment is the next step.

For some information on Lyme Disease treatment, have a look at How to treat Lyme Disease

Doctors may also wish to check other routine laboratory tests to determine how severely the patient's body has been affected by the Lyme disease. Other blood tests include:

  • White Blood Cell Count
  • Sedimentary Rate.

These tests are helpful to determine if the bacteria has spread throughout the body. Testing of synovial fluid and cerebrospinal fluid may be needed if the patient presents with Lyme disease induced arthritis or Lyme disease induced meningitis.

Deciding what tests to do depends on the physical clinical tests and the symptoms at that moment in time. The standard of care is to evaluate the patient's symptoms to determine the appropriate Lyme disease blood test, which then tells the doctor what the best treatment would be.