Testing for co-infections is even more difficult as many tick-borne diseases are newly emerging and/or not widely researched. Co-infection tests tend to be unreliable and the presence of a coinfection can skew the accuracy of testing for other infections as well.
Aside from accuracy issues with the ELISA and Western blot tests, in their current form they are not supposed to be used as diagnostic tools for physicians. Their intended use, as dictated by the Centers for Disease Control (CDC), is for surveillance purposes only. The CDC meant the tests main purpose to be for monitoring how much Lyme was occurring where not as a catchall for every case or to be used to diagnose an actual patient. Despite this most physicians defer to the given results and trust the tests to be accurate.
In general, you are likely to be tested with the ELISA test first and if positive, then tested with the Western Blot. Some physicians will do both tests at once, but this is not guaranteed and based on their personal preference.
The ELISA is run to measure your antibody response to the Lyme bacteria and a positive is based off of how many antibody bands make themselves evident, through IgM (new infection) and IgG (older infection). How many bands you need tends to range from doctor to doctor.
A Lyme-literate doctor may be willing to make a diagnosis with one positive Lyme-specific band. However, a general practitioner will likely require you to have two positive bands out of three on the IgM and three to five positive bands out of ten on the IgG. The amount of positive bands needed for diagnosis varies greatly from physician to physician. It’s very inconsistent system.
It should be noted that Lyme disease must be a clinical diagnosis! Relying solely on lab tests can lead to disastrous results and serious complications if a patient is not treated early enough. Lyme-literate doctors do not rely on bloodwork for diagnostic purposes. Even the CDC admits that Lyme disease should be a clinical diagnosis (based on symptomology and exposure history) not just on blood tests.
Patients rarely test CDC positive (your test aligns perfectly with CDC standards), because the CDC’s diagnostic protocol is too narrow to catch most cases and relies on the assumption that the tests are very accurate. Results not deemed definitively positive are often viewed as a false positive or negative result.
The timing of your test also matters. It is a common practice to be tested directly following a tick bite and this is absolutely not want you want to do. The tick itself can be tested (if able) but it can take up to 4-6 weeks for antibodies to appear. This leads to many false negative tests.
The Western Blot’s purpose is to visualize the exact antibodies you are making. This is used to determine whether an infection is older/recurrent or a new infection. Not every patient is going to test for antibodies every time. Some patients also suffer from seronegative Lyme disease where they don't ever test positive regardless of how many times they are tested or how active their infection is.
Both the ELISA and Western Blot are reliant on your body producing antibodies, so in the case of seronegative Lyme or in someone with a compromised immune system this adds to their already unsteady reliability. Both tests also rely on the Lyme bacteria staying in your bloodstream. Not long after infection the bacteria, given their corkscrew shape, tend to burrow out of the bloodstream and into the organs, tissues and joints, putting them out of range of the tests. Through various chemical processes the bacteria are also able to suppress and evade the immune system as well.
The current two-tiered testing system has been muddled even further by the CDC through the removal of bands 31 and 34, both which are specific to Lyme disease. These bands were removed due to vaccine trials. 31 and 34 were included in the vaccine and removed from the tests so individuals who had been vaccinated would not be mistaken as positive. The vaccine ended up being a failed product and was removed from the market. The removal of those two bands however has remained intact, with two possibilities for diagnosis already taken away before you've even been tested.
However, there are now numerous companies with tests available that include these bands and some that will report the results three ways: positive, negative and indeterminate.
There is also a lot of research going on surrounding new and better tests, more than could possibly be included in this educational packet. For more information on Lyme testing go to:
Antibody Bands: The Details You Need to Know!
Some bands are of more interest on the tests than others. Bands 23-25, 31, 34, 39 and 93 (same as 83) are considered highly specific to Lyme disease. Bands 18 and 41 are open to debate.
Below is a listing of each band and a brief explanation of what it represents.
18: An outer surface protein.
22: Possibly a variant of outer surface protein C.
23-25: Outer surface protein C (Osp C).
28: An outer surface protein.
30: Possibly a variant of outer surface protein A.
31: Outer surface protein A (Osp A).
34: Outer surface protein B (Osp B).
37: Unknown, but is considered a Borrelia-associated antibody. Some labs find it significant.
39: Unknown what this antigen is, but based on research other Borrelia do not even have the genetics to code for the 39 antigen. It is the most specific antibody for Borrelia.
41: Flagella or tail. This is how Borrelia burgdorferi moves, by utilizing the flagella. This band is considered to be cross-reactive and not entirely accurate on its own. It is the most common Borrelia antibody.
45: Heat shock protein. This helps the bacteria survive high temperatures. The only bacterium in the world that does not have heat shock proteins is Treponema pallidum, the cause of syphilis.
58: Heat shock protein.
66: Heat shock protein. This is the second most common Borrelia antibody.
73: Heat shock protein.
83/93: This is the DNA of Borrelia burgdorferi. It is the same as the 93. Varied significance is given between 83 vs. 93. They are however reported separately on tests.
Information sourced from International Lyme and Associated Diseases Society and LymeDisease.org