Lyme disease is a tick-borne illness spread by Lyme borreliae bacteria which includes, but is not limited to, Borrelia burgdorferi sensu stricto. The Centers for Disease Control and Prevention (CDC) estimate that there are 400,000 cases of Lyme disease annually, making Lyme a serious public health concern that only stands to grow as the spread of ticks affects disease endemicity and seasonality.
One of the biggest challenges of fighting Lyme disease is providing patients with accurate diagnostic tests. Without access to the best tests for Lyme disease, it’s impossible to diagnose this treatable disease in a timely manner. When the disease isn’t caught in time, it can spread throughout the body and cause chronic health problems that could otherwise be avoided with earlier detection and treatment.
How is Lyme disease diagnosed?
Though several types of tests do exist for the diagnosis of Lyme disease, the best tests for a Lyme disease diagnosis (and those recommended by the CDC) are blood tests, also known as serological tests. These tests are indirect, meaning they don’t detect the infecting bacteria or its antigens but rather the antibodies an infected person’s body produces in response to these antigens.
The most common Lyme disease blood tests
The two most common diagnostic tests for Lyme disease are the enzyme-linked immunosorbent assay (ELISA) and the Western blot. These Lyme disease tests allow physicians to visualize the reaction between antibodies in an infected person’s blood to specific antigens or parts of the bacteria that cause Lyme disease.
In the case of the Western blot, for example, antigens are separated by size and then transferred onto a membrane strip. When an antibody reacts with an antigen on the strip, that band will turn dark purple. For test results to be positive, a specific combination of bands on the membrane strip must be present.
The limitations of the ELISA and Western blot
Traditional Lyme disease tests are not specific enough.
Lyme disease is caused by the spiral-shaped bacteria Borrelia. There are multiple species and strains of Lyme borreliae (Lb). Therefore, tests must be targeted to these multiple species and strains in order to be able to detect them. If a patient is infected with a species or strain of Lyme borreliae that their test can’t detect, they will get a false-negative test result and thus risk missing their diagnosis. This can be costly and dangerous.
Many ELISA and Western blot Lyme disease tests are only equipped to detect one strain of one species of Borrelia: Borrelia burgdorferi B31 (Bb ss B31). This means that those tests are missing infections caused by other strains and/or species of Lyme borreliae.
In one internal study (PDF) designed to test the validity of the IGeneX ImmunoBlot against traditional Western blot tests, a total of 132 patients were tested by both Lyme Western blots and Lyme IB. 43 patients were seropositive on the ImmunoBlot, and 14 were positive on standard Western blots prepared from a mixture of two species for Bb ss B31 and 297. Thus 29 of the 43 patients tested negative on Western blots – i.e., the Western blot totally missed their infections with strains other than Bb ss B31 and 297.
With such limited tests, patients infected with non-B31 species and strains – e.g., B. mayonii, B. californiensis, or European species– are at risk of receiving false negatives and missing the chance to treat their diseases.
The ELISA and Western blot are not sensitive enough.
Another major limiting factor of the traditional ELISA and Western blot is the quality. These tests tend to use lysed BB cultures, and therefore, depending on the culture conditions, some antigens are over-expressed, and some are under-expressed. This, in turn, can affect the ability to detect antibodies from patients’ blood.
What’s more, if a patient tests too early after a tick bite, his or her body may not have produced enough antibodies to show up on a test with suboptimal sensitivity.
The problem with two-tier testing
The CDC recommends a two-tier testing process. The first test is usually an ELISA. If the patient is seropositive or indeterminate on the ELISA, a second test is performed – usually a Western blot. If the first test is negative, however, no further testing is recommended by the CDC.
According to CDC guidelines, a patient must test positive or indeterminate by ELISA and positive by Western blot tests in order to be diagnosed with Lyme disease.
Given the limitations in specificity and sensitivity of ELISA and the Western blot discussed above, it’s easy to see how the current two-tier testing system is insufficient. The first-tier ELISA is at best about 70-75% sensitive, and that’s for Bb ss strain B31 alone. That leaves a significant portion of patients with false negatives, who then never take a second test.
The IGeneX Lyme ImmunoBlot solves these problems.
IGeneX has developed a serological test that increases specificity without sacrificing sensitivity that has changed how to test for Lyme disease. It uses specifically created recombinant proteins from multiple species and strains of Lyme borreliae and reduces inconsistencies in reading and interpreting the test bands.
More species detected – The Lyme ImmunoBlot tests for more species of Lyme borreliae than the traditional ELISA and Western blot tests, reducing the risks of false negatives due to the inability to detect antibodies to a certain strain or species of Lb. The test includes all Borrelia-specific antigens relevant in North America and Europe, not just B. burgdorferi B31 or 297.
The result is a single test that replaces at least 8 Western blots.
More accurate testing – The ImmunoBlot uses specific recombinant proteins that are sprayed in precise amounts onto specific locations on the membrane strip, allowing for greater control of the quantity and location of the antigens. This makes reading the bands much more accurate and consistent.
Earlier detection – The ImmunoBlot can detect infections at multiple stages of illness, letting you catch (and treat) infections earlier.
The IgM and IgG ImmunoBlots’ superior specificity and sensitivity make them the best Lyme disease test available.
Learn more about IGeneX testing
Without accurate, multi-species tests that can detect infection at all stages of disease, patients can’t get a diagnosis and can’t get better. IGeneX is creating tests to solve this problem, including the ImmunoBlot and beyond. Learn more about the IGeneX tests (and tick-borne diseases they test for) today.