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Have you recently been bitten by a tick, and have you perhaps noticed that notorious bull's eye rash? Here's what you need to know about the diagnostic process you can expect if you think you may have Lyme Disease.

The symptoms of the tick-borne Lyme Disease are, to put it plainly, bad at every stage. Symptoms include fever, muscle and joint pain, a stiff neck, headaches, a feeling of general malaise, heart palpitations, shortness of breath, chest pain, fatigue, Bell's Palsy, swollen joints, muscle weakness, and cognitive problems. [1] There's no way to make that into an elegant sentence, and no easy way to live with all those symptoms.

As decidedly noticeable as the symptoms of (chronic) Lyme Disease are, they are not distinct enough to lead to a diagnosis on their own.

People who do notice a bull's eye rash (erythema migrans) have a major clue. Not all people with Lyme Disease have or notice a bull's eye rash, however, and dark-skinned people are especially likely to miss them [2]. Furthermore, not all cases of erythema migrans are caused by Lyme Disease [3]. People living in areas where ticks are prevalent have a clue too, but no definite answer.

It is, in short, impossible to determine whether or not you have Lyme Disease without laboratory diagnostic tests. Lyme Disease is unusual in that the tests do not look for the causative bacteria, Borrelia burgdorferi, directly, but rather for antibodies to it. For this purpose, the Centers for Disease Control and Prevention recommend a two-step diagnostic process [4]. 

Step One In The Diagnosis Of Lyme Disease: An Enzyme Immunoassay (EIA) Test

Enzyme immunoassay tests were developed in the 1970s and while they're scientifically rather complicated for laypeople (you and me both, reader!) to understand, they basically look for the presence of antibodies by having them bind to an antigen, a toxin or foreign body that produces an immune response. [5] The EIA test most commonly used to test for Lyme Disease is the enzyme-linked immunosorbent assay (ELISA) test. The CDC likewise acknowledges the so-called "ELFA" (enzyme-linked fluorescent immunoassay) test as a valid method of testing for Lyme Disease [6]. 

What do you, the patient, need to know? Basically, that a lab technician will take your blood and work their science on it. A negative ELISA or ELFA test means no Borrelia burgdorferi antibodies were detected in your blood. This typically means that you do not have Lyme Disease, but if the test is carried out very soon after a tick bite, you may test negative even if you do have Lyme Disease. For this reason, your physician may recommend that you wait a while before having the test, or that you repeat it later if it does come back negative.

A positive test means that antibodies were indeed detected, but a false positive test can show up when other infections are present [6]. This is why you move onto the next stage in the diagnostic process once you have a positive ELISA test. 

The Western Blot Test: IgM And IgG

The Western Blot test is the second stage in the Lyme Disease diagnostic process, and it identifies specific antibodies [7]. 

People who have been suffering from Lyme Disease symptoms for 30 days or less should have two tests [4]:

  • A test for Immunoglobulin M (IgM), the first antibody the body will start circulating once it encounters a new infection. 
  • A test for Immunoglobulin G (IgG), the most common antibody. It may be present in people with stage 1 Lyme Disease, but it may also take a few months to develop.

Those who have had signs of Lyme Disease for a month or longer should, meanwhile, only have the IgG test, as IgM will usually no longer be found at this stage [4]. You'll have moderate to high IgG reactions even years after the initial infection if your Lyme Disease went undiagnosed and untreated [8], so this particular lab test has no expiry date. 

Patients might like to know that no separate blood sample is required for the Western Blot tests — your lab technician can use the same sample they used for the ELISA test. 

Lyme Disease Tests The CDC Does Not Recommend

Individual labs may suggest or recommend other tests for Lyme Disease, but the CDC does not recommend a diagnostic process for Lyme Disease besides the one laid out above. Tests the CDC does not recommend include, but are not limited to, IgM and IgG tests without a previous EIA, capture assays for antigens in urine, and measuring antibodies in the fluid of your joints. [9] (To get the full list, click on the reference!)

In Conclusion

Folks who notice a bull's eye rash or know they were bitten by a tick may be asked to have an ELISA test when they see their physician soon after, but will either be asked to wait a while or to repeat it later on if it comes back negative. For the rest of us, the current diagnostic process for Lyme Disease works well. People who have show no evidence of the presence of Borrelia burgdorferi have no reason to suspect they are suffering from Lyme Disease if the diagnostic protocol was followed. 

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