Diagnosis

Lyme disease diagnosis

Lyme disease diagnosis remains a major challenge. While research is now well advanced compared with 1980, there is currently no reliable test to diagnose the disease. At present, the tests available have several limitations, especially for those in the chronic stage of the disease. The majority of available tests are far more effective in the acute stage of the disease.

Tests in Quebec

In Quebec, the diagnosis of Lyme disease is currently based on recommendations made by the INESSS. Health professionals therefore use indirect blood tests, i.e. tests to determine the patient’s immune response to the bacteria. The first step once a doctor suspects the disease is to take a commercial ELISA blood test. If the result of this test is negative, the sample is declared negative for antibodies against B. burgdorferi and does not undergo further analysis. If the result is positive or inconclusive, a second test, the commercial Western Blot (WB), is performed. In Canada, a person is considered to have Lyme disease only if their ELISA test and Canadian WB test are positive. It is only then that the case is reported under Quebec’s notifiable disease regulations. As the Canadian ELISA and WB tests have significant limitations in terms of sensitivity (the probability of a positive test in an infected subject), their interpretation remains the subject of much medical controversy. The INESS recognizes that these tests have several limitations and recommends the use of clinical judgment.

Here’s a link to the official INESSS documents, including the diagnostic tool and serology explanation tool:

See the INESSS diagnostic tool

See the INESSS serological tool

Clinical diagnosis concept

It’s important to note that a negative test result does not necessarily mean that a person isn’t infected with Lyme disease. Several patients, particularly those with the chronic form, obtain negative test results. It is therefore imperative that the notion of clinical diagnosis be introduced, namely based on the doctor’s clinical assessment. Laboratory results alone should not constitute the primary basis for diagnosis or treatment decisions. Lyme disease test kits have sensitivity and specificity limits, and are the source of much medical controversy. Healthcare professionals must understand these limitations and are urged to report any suspicious incidents, including false-positive and false-negative results, to Health Canada.

Here are a few reasons for a negative result in someone with the disease

The test is performed too quickly after exposure (bite): Patients generally take a few weeks to develop antibodies to the disease.
Patients suffering from the chronic form have a defective immune system: in this case, the patient’s immune system becomes so weak that antibodies are unlikely to be present.
The antibodies are practically all attached to the antigens in what is known as an immune complex, leaving no free antibodies to be detected in the blood.
There are almost 300 Borrelia subspecies. The tests cover only some of them, meaning that patients may be infected with a strain that has not yet been tested by the laboratory.
The patient’s symptoms may be explained by co-infection rather than Borrelia infection. For example, tick-borne fever (TBRF) often creates symptoms similar to Lyme, which means patients will test negative, hence the importance of looking for co-infections.
The bacteria may not be present in the blood at the time of testing, but hidden in other tissues.

Interestingly, in cases of suspected Lyme disease, despite a negative test result, the American CDC (Centers for Disease Control and Prevention) recommends against relying on the test, but rather treating on the basis of clinical judgment.

The doctor consulted must also consider the possibility that your symptoms are due to Lyme disease. The unfortunate truth is that, at the moment, this disease is hardly considered by Quebec doctors.

In order to help with clinical diagnosis, Dr. Horowitz, a New York State physician with over 25 years’ experience with Lyme disease, treating more than 12,000 patients and publishing several books on the subject, has created a questionnaire. Here is the Horowitz Questionnaire. It will allow you to determine the probability of having Lyme disease and the multi-systemic infectious syndrome that occurs with the advanced form of the disease:

Download PDF

To fully understand the tests, it is important to know that there are two different ways of testing for the disease

The direct method

Direct testing consists of directly looking for the pathogen’s presence in the body, i.e. in blood, body fluids or even tissues. Direct methods include tests such as: culture, PCR, cePCR, FISH.

The indirect method

Indirect tests consist in measuring the patient’s immune response to the pathogen. When the body is invaded by Lyme spirochaetes, the immune system responds to foreign antigens by producing antibodies to fight the infection. Indirect tests therefore do not detect the presence of the bacteria in the body, but rather the body’s response to infection (by detecting antibodies). Indirect methods include tests such as: ELISA (enzyme-linked immuno-sorbent assay), WesternBlot (immunoblotting), EIA (Enzyme-linked immune assay).

International testing

As previously mentioned, the tests currently available in Quebec have several limitations. As a result, many people turn to international laboratories for a more comprehensive set of tests, including direct and indirect methods, along with tests for different strains and co-infections:

Here are a few links to well-known laboratories outside the country:

IGENEX – ARMINLABS – GALAXY – VIBRANT WELLNESS

*It must be noted that the results of these tests are not currently recognized here in Canada.

Controversy

Canada’s public health agency has based its recommendations on guidelines adopted by the American CDC (Centers for Diseases Control). While the CDC recommends a positive ELISA result prior to Western blot testing, an increasing number of studies are revealing the flaws in this two-part diagnostic approach. According to the following report, Lyme infections are not detected by the currently recommended method in an average of 44% of cases. While this method is simple, easy to use and inexpensive, it’s far from optimal.

Find out more about the controversy