Testing for Lyme disease

I get frequent questions about testing for Lyme. Lyme is an umbrella term for bacterial, parasitic, and viral infections transmitted by tick bite. Many of the same organisms are transmitted by mosquito, biting flies, fleas, and even spiders. However, ticks have specialized mouth anatomy and saliva which disables our immune defenses at the bite. The Lyme bacteria is named Borrelia burgdorferi. Some other organisms ticks share are Bartonella, Ehrlichia, Anaplsma, Mycoplasma, and Babesia. These are co-infections. In addition, there are multiple strains of Borrelia in North America.

A thorough explanation of the controversy regarding Lyme testing and treatment is given in Cure Unknown: Inside the Lyme Epidemic by Pamela Weintraub, Science Editor for Discover Magazine.
The info which follows focuses on aspects I believe relevant to providing good patient care:

  1. The CDC standard screening test is ELISA antibody testing for Borrelia burgdorferi. This test is negative in half the patients who actually are infected with Borrelia. If this test is negative, then physicians typically conclude the patient doesn’t have Lyme disease.
  2. If the Lyme ELISA test is positive, then Western Blots for IgG and IgM antibodies to Borrelia are done. This test looks at antibodies made by the patient’s immune system to several Borrelia proteins. To get a CDC reportable diagnosis of Lyme disease on a Western Blot, the sample needs to react to 5 proteins on the IgG antibody test or 2 proteins on the IgM test. However, if the immune system is making antibodies to any single Borrelia protein, then it is reasonable to conclude the infection is present. Western Blot for Lyme is where I start the lab investigation. There are several pertinent issues regarding interpretation of Lyme Western Blot tests:
    1. Borrelia proteins used for human testing are always from a specific Borrelia strain found on Long Island in the 1980’s. There are many other Borrelia strains in the US known to cause Lyme disease symptoms, but proteins from these strains are not used in testing.
    2. Because a vaccine has been in development since the 1990’s, the CDC does not allow inclusion of 2 of the most specific Borrelia proteins in test kits sold to labs. The only way to test these 2 proteins is to send the sample to a lab which produces their test reagents in house. The labs in the US providing complete Western Blot Lyme panels are: IgeneX in California, Coppe Lab in Wisconsin, and Clongen on the East Coast.
    3. If the immune system is producing antibodies to any Borrelia specific protein, the patient has symptoms consistent with Lyme and hasn’t been treated, the bacteria is most likely present.
  3. The red blood cell parasite Babesia requires a different medicatons. If patients have symptoms of Babesia, especially drenching sweats, I recommend an antibody test for this organism.
  4. Testing for other tick borne organisms can also be done. Discussion of this topic is too complex for this venue.
  5. Body fluids like blood, serum, or urine can be tested for the genetic material of Borrelia. This type of test is called PCR, and depends on the presence of bacterial material in the body fluid being tested. This test is useful in cases where the immune system fails to mount a defense by making antibodies. Because the ELISA and Western Blot test both look for antibodies, PCR for Lyme can be positive when all antibody tests are negative. But because the Borrelia likes to burrow through tissues, PCR will be negative if there are no Borrelia in the sample being tested.