Tips about Ticks – Part 3

Tips about Ticks:

A 6-Part Overview of Lyme Disease, Co-infections, Diagnosis, Conventional and Alternative Treatments, Complications and Prevention Strategies

By Dr. Deanna Walker and Dr. Rahima Hirji

PART 3: How is Lyme Disease diagnosed?

There is a lot of controversy about how Lyme Disease should be diagnosed. Many believe that Lyme Disease should be based on clinical signs and symptoms rather than lab testing. This is because the lack of sensitivity in the recommended testing methods means that a negative results does not rule out the possibility of Lyme Disease. It is important to note that people who develop an erythma migraines rash (bull’s eye rash) in an endemic area of ticks that carry B. burgdorferi do not require confirmation with testing. Treatment should occur regardless.

Different testing options

Direct testing:

• Culture: This involves taking a sample from tissue, joint fluid or blood, putting it in a medium to promote bacterial grow. This method is not typically used because B. burgdorferi is difficult to grow and there are many variables that reduce the sensitivity of the test such as timing and specimen used.
• Polymerase chain reaction (PCR): This process takes DNA sample from tissue (skin), joint fluid or blood and makes many copies from a single sequence of a gene. This allows for the discovery of small traces of bacterial DNA. This test has low sensitivity and better specificity but contamination can occur. This test is gaining more popularity but still rarely done by conventional doctors.

Indirect testing:

• Serology: These are the most common tests used. It involves a blood sample and evaluation of the serum component of the blood. In this test, you are looking for antibodies that have been produced in response to an infection. The 2 main types are ELISA (enzyme-linked immunosorbent assay) and Western Blot. Both measure the IgM and IgG antibody levels to B. burgdorferi antigens.
  • ELISA detects antibodies to B. burgdorferi. It is not used as a sole test to diagnosis Lyme because it can result in many false-positives (people who get a positive result but are not infected by B. burgdorferi). This test is also not sensitive for early lyme because an antibody response takes time to develop. If the ELISA test is positive, the diagnosis must be confirmed with Western blot.
  • Western blot detects antibodies to several proteins of B. burgdorferi. There are a certain number of specific bands that must be present in the Western blot in order for the test to be positive. IgM and IgG antibiodies are the antibiodies detected against specific B. burgdorferi proteins/antigens.
• Lymphocyte Transformation Test (LTT): this test measures the T cell response to B. burgdorferi antigens. T cells are a type of white blood cell (immune cell) that respond independently from antibodies and appear to follow disease activity. This is a fairly new test and studies that have been done with this test claim to have greater sensitivity and specificity than the recommended 2-tiered testing. This test is rarely used because of the novelty of it.

For diagnosis, most physicians follow the guidelines set by the CDC (Centers for Disease Control and Prevention). Their guidelines are as follows:

CDC diagnostic criteria

CDC recommends “two-tiered testing” process when testing blood for evidence of antibodies against the Lyme disease bacteria. Both steps can be done using the same blood sample. The first tier involves a testing procedure called EIA (enzyme immunoassay) or more commonly known as ELISA. If this first step is negative, no further testing of the sample is recommended. If the first step is positive or indeterminate, the second tier should be performed. The second tier uses a test called an immunoblot test, commonly known as the Western blot test. Results are only considered positive for Lyme borreliosis if the EIA and the immunoblot are both positive. The CDC does not recommend skipping the first tier and doing the Western blot. There is a 70-80% sensitivity for each tier and together with the recommended two-tier testing, the sensitivity is only 50-65%. The reason for this is that there are many different ELISA and Western blot tests available, none of which are consistent or FDA approved. Other factors that affect the sensitivity of these tests are the disease duration, prior antibiotic treatment and the test manufacturer.

Overall a diagnosis for Lyme is confirmed in the following circumstances:

1. Positive culture
2. Positive two-tier serology testing
3. Positive single-tier IgG serology testing with Western blot

Other:

1. EM rash in an endemic area
2. Clinical signs and symptoms**

Stay tuned to Part 4 of our Lyme posts on conventional treatment options.